LIBRARY 
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SECRETS  OF  ANIMAL  LIFE 


BY  THE  SAME  AUTHOR 


A  STUDY  OF  ANIMATE  NATURE 

2  volumes 

THE  SECRETS  OF  ANIMAL  LIFE 
THE  WONDER  OF  LIFE 
THE  BIOLOGY  OF  THE  SEASONS 
DARWINISM  AND  HUMAN  LIFE 

New  Edition 

INTRODUCTION  TO  SCIENCE 

Volume  21  in  the 

Home  University  Library 


IOLT  AND  COMPANY 

S  NEW    YORK 


SECRETS  OF 
ANIMAL  LIFE 


BY 

J.  ARTHUR  THOMSON 

M.A.,  LL.D. 

REGIUS   PROFESSOR  OF  NATURAL  HISTORY  IN  THE 
UNIVERSITY  OF  ABERDEEN 


NEW  YORK 

HENRY  HOLT  AND  COMPANY 

1919 


COPYRIGHT,  1919 

BY 

HENRY  HOLT  AND  COMPANY 


gfte  autnn  &  goben    Companp 

BOOK      MANUFACTURERS 
RAHWAY  NEW     JERSEY 


PREFACE 

' 

'"T^HE  aim  of  this  book  of  short  studies  is  to 
•*•  interest  thoughtful  readers  in  the  multitudi- 
nous problems  of  animal  life  as  they  present  them- 
selves to  the  modern  biologist.  Some  of  them  deal 
with  old  problems  which  have  reasserted  themselves 
in  new  guise;  others  deal  with  new  problems  which 
recent  research  has  brought  into  prominence.  Most 
of  them  are  confessedly  appreciations  of,  and  re- 
flections on,  the  investigations  of  other  naturalists, 
and  most  of  them  were,  to  begin  with,  "  lectures  " 
to  senior  students  of  Natural  History  in  this  Uni- 
versity. It  need  hardly  be  said  that  the  subjects 
chosen  are  only  representative,  and  that  the  light 
thrown  on  them  tends  rather  to  an  appreciation 
than  to  a  solution  of  the  problems  involved.  Nature 
so  often  tells  us  one  secret  in  terms  of  another. 
The  first  ten  studies  deal  with  individual  animals; 
the  next  six  have  to  do  with  the  web  of  life;  the 
ten  that  follow  raise  problems  of  development  and 
behavior — two  subjects  more  intimately  related 
than  appears  at  first  sight;  the  remaining  fourteen 

in 


ir  PREFACE 

studies  may  be  grouped  round  the  concept  of  evo- 
lution. All  the  studies  appeared  in  The  New 
Statesman  and  are  published  in  this  form  with  the 
kind  permission  of  the  proprietors  and  editor. 

J.  ARTHUR  THOMSON. 

MAMSCHAL  COLLEGE, 

THE  UNIVERSITY  OF  ABERDEEN, 
January   1919. 


CONTENTS 

VAGI 

I.   HOMING  OF  SEA-SWALLOWS    .       ,  i 

II.    A  PECULIAR  PEOPLE        ...  9 

III.  RAIDS  OF  THE  AMAZON  ANTS  .       .  17 

IV.  SOCIAL  LIFE  OF  WASPS     .       .       .  24 
V.    THE  CAWING  OF  ROOKS  .       .       .  32 

VI.    CUCKOO  PUZZLES      ....  39 

VII.    THE  FROG'S  YEAR     ....  47 

VIII.    THE  EDUCABILITY  OF  A  SNAIL       .  55 

IX.    THE  CULT  OF  SHELLS      ...  62 

X.   THE  FITNESS  OF  RIGHT  WHALES    .  71 

XI.    THE  INTERNAL  ECONOMY  OF  THE 

SEA  . 80 

XII.    SEA-MEADOWS 88 

XIII.  FRANKINCENSE  AND  MYRRH    .       .  95 

XIV.  COUNTRY  SOUNDS     ....  103 
XV.    THE  FALL  OF  THE  YEAR  .       .       ...  1 1 1 

XVI.    THE  SURVIVAL  OF  THE  OTTER      -.-  120 

XVII.    MIDWINTER 127 

XVIII.   THE  MICROCOSM  OF  THE  EGG  .       .  134 

.   T 


vi  CONTENTS 


PAGZ 


XIX.  THE  CURVE  OF  LIFE    .       .       .142 

XX.  REJUVENESCENCE        .       .       .150 

XXI.  THE  BIOLOGY  OF  TWINS    .       .158 

XXII.  A  LIMB  FOR  A  LIFE    .       .       .     166 

XXIII.  LATENT  LIFE       .       .       .       .     175 

XXIV.  THE  STORING  INSTINCT     .       .     183 
XXV.  THE  ROVING  IMPULSE       .       .191 

XXVI.  THE  PROBLEM  OF  PARASITISM  .     198 

XXVII.  WONDERS  OF  INSTINCT       .      .       206 

XXVIII.  MAKING  A  HOME  FOR  LIFE       .     213 

XXIX.  WITH  DARWIN  FORWARDS        .     221 

XXX.  THE  MENDELIAN  CLUE      .        .     229 

XXXI.  THE  FOUNTAIN  OF  CHANGE     .     238 

XXXII.  PROBLEM  OF  CAVE  BLINDNESS  .     246 

XXXIII.  CONVERGENCE  IN  EVOLUTION    .     254 

XXXIV.  DOES  ACQUIRED  VIGOR  COUNT?    263 
XXXV.  THE  UNSEEN  GOAL  ...     270 

XXXVI.  BEFORE  THE  DAWN  OF  ART      .     278 

XXXVII.  MAN'S  ARBOREAL  APPRENTICE- 
SHIP          287 

XXXVIII.  SEQUEL  TO  "  THE  JUKES  "       .     294 

XXXIX.  THE  OPTIMISM  OF  PATHOLOGY    302 

XL.  THE  CULT  OF  JOY      .       .       .     309 


SECRETS  OF  ANIMAL  LIFE 


HOMING  OF  SEA-SWALLOWS 

HOMING  pigeons  have  been  used  by  man  for 
more  than  two  thousand  years,  and  still  we 
have  no  satisfactory  theory  of  their  usually  success- 
ful return  from  great  distances  to  their  cots.  Still 
less  can  we  explain  the  well-authenticated  fact  that 
a  swallow  may  return  from  its  wintering  in  the  south 
to  the  Scottish  farm-steading  where  it  was  born 
the  year  before.  The  problem  of  homing  bristles 
with  difficulties,  and  it  is  therefore  with  eagerness 
that  we  turn  to  a  record  of  the  experiments *  which 
have  been  recently  made  on  the  sea-swallows  at 
the  Tortugas  by  Professor  J.  B.  Watson  and  Dr.  K. 
S.  Lashley.  The  birds  were  the  Noddy  Tern  and 
the  Sooty  Tern,  which  breed  in  tens  of  thousands 
upon  Bird  Key.  That  island  of  the  Tortugas  group 
was  surely  predestined  for  the  experiments  in 
question,  for  it  is  the  northern  limit  of  the  migration 
of  these  two  tropical  terns,  so  that  if  the  birds  are 
taken  anywhere  to  the  north  they  will  find  them- 

1  Papers  from  the  Department  of  Marine  Zoology,  Carnegie 
Institution,  Washington,  vii.  (1915)  pp.  1-104,  7  p!s.  9  figs. 

1 


ANIMAL  LIFE 


selves  in  all  probability  in  a  region  which  they 
never  before  visited.  Furthermore,  as  Bird  Key  is 
the  last  piece  of  land  between  the  coast  of  Florida 
and  the  coast  of  Texas,  the  birds  can  be  sent  out  to 
sea  for  hundreds  of  miles  beyond  sight  of  all  land- 
marks. Between  Bird  Key  and  Galveston,  for 
instance,  there  is  open  water  for  855  statute  miles, 
obviously  a  fine  expanse  for  homing  experiments. 

The  technique  of  the  experiments  is  as  follows  : 
A  bold,  vigorous  tern  is  caught,  it  is  marked  char- 
acteristically with  oil-paint  on  the  head  and  neck; 
two  tags  (small  and  large,  but  otherwise  duplicate) 
are  prepared,  recording  the  date,  the  place,  and  the 
kind  of  marking;  the  small  tag  is  tied  round  the 
bird's  neck;  the  large  tag  is  fixed  to  a  foot-long 
stake  pushed  down  into  the  sand  near  the  nest  if 
the  bird  is  a  Sooty  or  tied  to  a  convenient  twig  if 
the  bird  is  a  Noddy;  the  bird  is  put  into  a  large 
hooded  cage  and  transported  to  a  distance  on 
board  ship  ;  it  is  kept  in  good  health  with  minnows 
from  the  refrigerator;  it  is  liberated  at  a  chosen 
point;  and  then  its  return  to  the  nest  is  watched 
for.  The  most  important  general  result  is  that 
these  terns  are  able  to  return  from  Galveston, 
more  than  800  miles  away,  over  a  body  of  water 
which  apparently  does  not  offer  any  basis  for  con- 
trolling flight  direction.  Some  returned  in  about 
six  days,  some  took  nearly  twelve,  some  did  not 
return  at  all.  Many  of  the  return  journeys  from 
distances  greater  than  500  miles  did  not  require 
more  than  three  to  five  days,  but  sometimes  as 


HOMING  OF  SEA-SWALLOWS  3 

long  a  time  was  required  to  come  from  Key  West 
to  Bird  Key,  which  is  only  about  65  miles.  It 
goes  without  saying  that  the  time  required  has 
nothing  to  do  with  the  rate  of  flight,  for  three 
Booties  returned  from  Key  West  in  3  hours  45 
minutes,  and  probably  spent  part  of  that  time  on 
the  feeding  ground  before  reporting  themselves 
at  the  nests.  The  success  of  the  homing  depends 
partly  on  the  vigor  of  the  birds  and  partly  on 
the  smiles  of  fortune,  as  expressed,  for  instance, 
in  a  spell  of  fine  weather  and  the  absence  of 
hawks. 

It  is  instructive  to  give  particulars  in  regard  to 
some  of  the  experiments.  Two  Noddies  and  two 
Sooties  were  taken  in  the  stateroom  of  a  steamer  to 
Havana,  and  liberated  in  the  harbor  there  early 
in  the  morning  of  nth  July.  They  returned  to 
Bird  Key  (108  miles  off)  next  day,  having  prob- 
ably spent  most  of  the  time  recuperating  around  the 
shores  of  Cuba.  Of  five  birds  liberated  off  Cape 
Hatteras  at  least  three  returned  in  a  few  days, 
having  accomplished  a  journey  of  850  miles  as 
the  crow  flies,  and  of  much  more  if  the  alongshore 
route  was  followed.  Four  Noddies  and  four  Sooties 
were  taken  in  a  hooded  cage  on  a  Galveston  steamer 
to  about  461  statute  miles  from  Bird  Key  and 
liberated  where  no  shore  line  was  visible.  "  On 
release  all  birds  with  one  exception  started  east. 
That  one  headed  west  and  continued  for  about 
200  yards,  then  turned  suddenly  and  started  east.'* 
They  had  a  strong  head  wind  against  them  through- 


3          SECRETS  OF  ANIMAL  LIFE 

out  the  first  day,  but  two  of  the  Noddies  returned 
in  safety  to  Bird  Key.  On  4th  June  eleven  birds 
were  liberated  in  Galveston  Harbor;  on  gth  June 
one  of  the  observers,  returning  to  Bird  Key  on 
the  steamer,  saw  one  of  his  terns  (a  red-marked 
Sooty)  resting  upon  a  piece  of  driftwood  in  the 
open  sea  about  409  statute  miles  east  of  Galveston. 
A  heavy  storm  unfortunately  removed  all  chance  of 
its  successful  return. 

The  authors  are  not  prepared  to  offer  any  solution 
of  the  problem  of  distant  orientation  in  birds,  but 
they  have  made  a  distinct  step  in  proving  that  un- 
trained birds  can  return  successfully  across  the 
apparently  trackless  sea  from  a  distance  of  800  to 
1000  miles.  Dr.  Lashley  has  shown  that  for  short 
distances  on  the  island  itself  the  terms  adjust  them- 
selves to  nest  and  mate  and  young  on  a  basis  largely 
of  visual  experience,  helped  a  little  by  memory  of 
movements,  and  sometimes  by  sounds.  There  is 
no  whit  of  evidence  of  any  unusual  sensitiveness 
nor  of  the  functioning  of  any  hypothetical  sense- 
organ. 

But  what  can  be  said  in  regard  to  distant  orien- 
tation? (i)  It  has  been  suggested  that  the  Cape 
Hatteras  birds  followed  the  coast-line  in  the  direction 
of  greater  warmth.  This  is  possible  enough,  but  it 
does  not  bear  at  all  upon  the  flight  from  Galveston 
to  Bird  Key  across  the  Gulf  of  Mexico.  (2)  It  has 
been  suggested  that  the  Galveston  birds  followed 
a  well-marked  water-current  which  sweeps  around 
the  coast  of  Texas,  Louisiana,  Alabama,  Florida, 


HOMING  OF  SEA-SWALLOWS  5 

and  out  past  Tortugas  through  the  Straits  of  Flor- 
ida. The  current  differs  in  color  from  the  surround- 
ing water  and  from  the  return  current  which  runs 
nearer  the  coast-line.  But  the  color  difference  is 
only  noticeable  when  the  sun  is  in  a  certain  position 
in  relation  to  the  observer;  many  of  the  successful 
birds  were  liberated  at  night,  and  all  were  out  for 
several  nights;  they  had  to  win  their  way  home 
through  rain,  haze,  and  cloudy  weather;  they 
homed  equally  well,  no  matter  at  what  point  between 
Galveston  and  the  Tortugas  they  were  put  down. 
And  besides,  why  should  they  not  follow  the  current 
in  the  opposite  direction?  (3)  It  has  been  sug- 
gested that  the  birds  get  their  bearings  visually 
by  ascending  to  a  great  height.  But,  in  the  first 
place,  they  never  seem  to  rise  very  high;  in  the 
second  place,  they  would  require  at  a  distance  of  100 
miles  to  ascend  almost  a  mile  to  see  the  Loggerhead 
Key  lighthouse;  and,  in  the  third  place,  even  if 
they  ascended  they  would  not  see  much  because  of 
the  continuous  haze. 

The  observers  are  not  inclined  to  assume  any  new; 
and  mysterious  "sense  of  direction"  until  they 
have  made  many  more  experiments,  and  a  good 
beginning  has  been  made.  Thus,  to  meet  Duchatel's 
hypothesis  that  the  retina  of  the  bird  is  specially 
sensitive  to  infra-luminous  rays,  especially  infra- 
red, Professor  Watson  made  a  special  investigation 
of  spectral  sensibility  in  the  chick  and  the  homing 
pigeon,  and  found  no  evidence  at  all  of  the  sup- 
posed susceptibility.  Care  was  also  taken  to  test 


6  SECRETS  OF  ANIMAL  LIFE 

Cyon's  theory  that  birds  (notoriously  deficient  in 
the  sense  of  smell  of  the  ordinary  kind)  nose  their 
way  home  through  the  air,  feeling  the  direction, 
strength,  and  temperature  of  the  wind  as  it  plays 
on  the  olfactory  mucous  membrane.  The  nasal 
chambers  of  two  Noddy  terns  were  filled  with  warm 
wax  and  varnished  over,  and  the  birds  were  sent 
to  Key  West,  65  miles  distant,  where  they  were 
released  at  two  o'clock  in  the  afternoon.  At  day- 
break next  morning  both  birds  were  on  their  nests 
just  as  usual.  Thus  it  may  be  inferred  that  there 
is  not  in  the  nasal  cavity  of  terns  any  special  tactile 
or  olfactory  sensitiveness  which  functions  in  the 
homing.  The  observers  propose  to  inquire  whether 
there  may  be  on  other  parts  of  the  body — such  as 
eyelids,  ear-covering,  mouth  cavity — any  tactile  or 
thermal  nerve  endings  which  may  assist  the  birds 
in  reacting  to  slight  differences  in  pressure,  tempera- 
ture, and  humidity  which  they  may  encounter  on 
their  flight. 

So  the  matter  stands  at  present — the  remarkable 
fact  of  untrained  birds  successfully  reaching  from  a 
great  distance  a  known  but  invisible  goal  surrounded 
by  apparently  trackless  sea.  It  goes  without  saying 
that  there  are  speculative  theories  galore,  but 
what  Professor  Watson  and  Dr.  Lashley  are  work- 
ing towards  is  a  scientific  interpretation.  Natural- 
ists have  appealed  to  magnetic  sense,  topographical 
memory,  registration  of  movements,  telepathy, 
and  so  on — at  least  nine  theories  have  been  advanced 
: — but  the  solution  of  the  riddle  is  still  in  the  future. 


HOMING  OF  SEA-SWALLOWS  7 

It  is  a  familiar  step  in  scientific  method  to  try  to 
bring  an  obscure  fact  into  line  with  others  of  an 
approximately  similar  kind,  and  this  must  be  done 
in  the  case  of  the  homing  terns.  In  this  connection 
it  is  unfortunate  that  the  data  in  regard  to  homing 
dogs  and  cats  and  other  mammals  are  not  in  a  form 
suitable  for  scientific  purposes,  and  that  crucial 
experiments  to  show  what  untrained  homing  pigeons 
can  do  are  lacking. 

Exceedingly  careful  experimental  work  has  been 
done  with  ants  and  bees,  which  find  their  way 
home  successfully  within  a  limited  radius,  and  the 
balance  of  evidence  inclines  to  the  conclusion  that 
most  of  the  phenomena  can  be  explained  by  the 
gradual  registration  of  various  sets  of  stimuli — 
olfactory,  tactile,  visual,  and  kinaesthetic.  Here 
also,  however,  there  are  residual  phenomena  at 
present  as  inexplicable  as  the  homing  of  the  terns 
from  Galveston  to  the  Tortugas.  Professor  Watson 
holds  the  chair  of  Experimental  and  Comparative 
Psychology  at  the  Johns  Hopkins  University,  and 
his  experimental  study  of  the  homing  terns  is 
marked  by  a  greater  psychological  subtlety  than  is 
usually  to  be  found  in  the  adventures  of  zoologists 
in  similar  fields.  Thus  it  is  interesting  to  notice  his 
careful  observations  on  the  duration  of  the  nesting 
impulse  when  the  normal  activities  have  been  inter- 
rupted. He  finds  that  it  remains  strong  for  two  or 
three  weeks ;  and  this  should  be  borne  in  mind,  for  it 
gives  an  illuminating  significance  to  the  homing  of 
the  sea-swallows.  They  are  returning  to  their  nests, 


8  SECRETS  OF  ANIMAL  LIFE 

that  is,  to  activities  in  which  their  life  reaches  its 
climax,  to  the  continuance  of  which  they  are  im- 
pelled by  a  deep  organic  urge,  by  an  irresistible 
impulse  which  is  not  balked  by  any  waste  of  seas, 


II 

A  PECULIAR  PEOPLE 

THE  story  goes  that  a  lady  seeing  penguins  for 
the  first  time,  and  that,  as  it  happened,  in 
the  sea-lions'  inclosure  at  the  Zoo,  remarked  that 
it  was  strange  that  the  young  seals  were  so  like 
birds.  She  might  well  be  excused  for  an  error 
that  showed  an  unprejudiced  mind,  for  quainter 
creatures  than  penguins  it  would  be  hard  to 
imagine.  Their  striking  attitudes,  now  upright 
like  sentinels  and  again  groveling  on  the  ice  like 
their  reptilian  ancestors;  their  versatility  in  move- 
ment, gamboling  like  porpoises,  swimming  like 
ducks,  diving  with  the  help  of  their  flippers  to 
a  depth  of  ten  fathoms,  toddling  on  the  ice  like  top- 
heavy  babies,  and  tobogganing  in  a  manner  all  their 
own;  their  daring  surrender  of  wings  in  exchange 
for  flippers;  their  way  of  molting  their  feathers 
in  great  patches;  and  a  score  of  other  remarkable 
features  mark  them  out  among  birds  as  a  very 
peculiar  people.  But  it  is  when  we  inquire  into 
their  habits  that  their  most  striking  peculiarities 
are  discovered,  and  here  we  are  especially  indebted 
to  Staff-Surgeon  Murray  Levick,  R.N.,  member  of 
the  "Terra  Nova"  (1910)  Antarctic  Expedition, 
who  has  got  nearer  the  heart  of  the  penguin — of  the 

9 


10  SECRETS  OF  ANIMAL  LIFE 

Adelie  species  at  least — than  any  previous  observ«r. 
The  work  of  Dr.  Edward  A.  Wilson,  whose  ua- 
timely  death  was  such  a  loss  both  to  science  and  art, 
remains  a  model  of  accuracy  and  thoroughness,  but 
Dr.  Levick  has  gone  further.  He  has  previously 
written  a  delightful  popular  study  of  the  social 
habits  of  the  Adelie  penguins  (Heinemann,  1914) ; 
what  we  have  before  us  now  is  an  excerpt  (1915) 
from  the  first  volume  of  the  British  Museum  Report 
on  the  zoological  discoveries  of  the  "  Terra 
Nova  "  Expedition.  It  is  entitled  Natural  History 
of  the  Adelie  Penguin,  and  is  illustrated  with 
twenty-one  remarkable  photographs.  It  is  a  study 
which  any  naturalist  might  be  proud  of,  and  it 
shows  the  author  to  be  an  observer  of  the  first  rank. 
The  observations  appeal  not  only  to  those  who  are 
keen  on  birds,  but  also  to  those  who  are  interested 
from  the  philosophical  side  in  the  deeper  problems 
of  natural  history.  "  You  of  any  well  that  springs," 
said  Meredith,  "  may  unfold  the  heaven  of  things/' 
and  it  is  extraordinary  how  "  far  ben  "  into  biology 
Dr.  Levick's  careful  study  leads  us. 

Towards  the  middle  of  October,  a  single  Adelie 
penguin  was  seen  on  the  rookery  at  Cape  Adare. 
Two  days  afterwards  there  were  two,  and  next  day 
about  a  score,  and  next  day  "as  we  looked  across 
the  sea-ice  to  the  northwards,  we  could  see  a  long 
line  of  Adelies  approaching,  tailing  out  in  snake- 
like  fashion,  as  far  as  the  horizon."  This  is  the  first 
picture,  the  return  of  the  penguins  to  their  birth- 
place. Dr.  Louis  Gain  of  the  Charcot  Expedition 


A  PECULIAR  PEOPLE  11 

has  proved  that  some  at  least  return  to  the  same 
rookeries  year  after  year  to  breed;  and  here  we  are 
out  of  our  depth  at  once  when  we  think  of  the 
mysterious  nostalgia  that  brings  these  flightless 
birds  back  to  their  cradle  over  hundreds  of  miles  of 
-trackless  sea.  When  they  get  agoing  on  the  ice 
they  toddle  hurriedly,  one  hundred  and  thirty  steps 
per  minute,  six  inches  at  a  step,  two-thirds  of  a  mile 
per  hour.  "  In  the  still  air  their  little  wheezy  respir- 
ation could  be  heard  distinctly,  and  they  seemed 
to  be  somewhat  out  of  breath."  Every  now  and 
then  they  suddenly  flop  forwards  on  their  breasts 
and  take  to  tobogganing  at  the  same  rate  as  before, 
using  their  legs  as  propellers.  By  the  end  of  the 
month  the  rookery  at  Cape  Adare  was  crammed 
with  some  three-quarters  of  a  million  birds. 

The  hens  take  possession  of  the  old  stone-nests 
or  scoop  out  new  hollows  in  the  ground,  and  wait — 
sometimes  rather  forlornly — for  proposals.  A  cock, 
struggling  against  the  drowsiness  engendered  by  the 
long  journey,  rouses  himself  to  action,  and  makes 
as  if  to  place  an  imaginary  stone  at  the  hen's  feet, 
"a  most  obvious  piece  of  dumb  show."  But  the 
hen  often  answers  never  a  word,  and  it  requires  a 
duel  between  rival  cocks  to  arouse  her  interest. 
The  combatants  lean  their  breasts  against  one 
another  and  rain  in  blows  with  their  flippers.  In 
many  cases  blood  is  drawn,  but  Dr.  Levick  never 
saw  a  fatal  encounter.  During  the  first  days  of 
wedded  life  the  cock  has  continually  to  make  good 
his  claim  by  driving  off  interlopers,  but  after  the 


12  SECRETS  OF  ANIMAL  LIFE 

pair  settle  down  they  remain  perfectly  faithful  to 
one  another. 

The  nests  are  made  of  rounded  stones  which  the 
'cock  collects,  stealing  them  when  he  can.  Jagged 
pieces  of  quartz  seemed  to  be  irresistible,  the  aesthetic 
triumphing  over  comfort,  and  there  was  an  eager 
demand  for  Dr.  Levick's  painted  pebbles,  red  being 
preferred  to  green.  A  very  interesting  feature  was 
the  entire  avoidance  of  a  big  knoll  rising  from  a 
shallow  lakelet  by  the  beach.  The  water  was  frozen 
hard  when  the  penguins  arrived,  but  the  wise  birds 
seemed  to  realize  (or  was  it  some  taboo-tradition?) 
that  in  some  six  weeks'  time  they  would  not  be  able 
to  reach  the  knoll  save  by  wading  through  muddy 
water  slimy  with  guano.  On  other  situations  the 
nests  were  occasionally  built  too  low,  and  a  good 
deal  of  energy  had  to  be  subsequently  expended  in 
raising  them  with  extra  stones  as  the  thaw-water 
accumulated.  A  pretty  incident  was  once  seen — 
a  cock  bringing  a  lump  of  snow  for  the  hen  to  eat. 
"The  cock,  when  away  from  his  mate,  evidently 
had  in  his  mind  the  fact  of  his  hen  being  thirsty  and 
unable  to  get  snow  as  he  could."  It  is  characteristic 
of  the  Adelie  penguins  to  climb  heights  and  nest  on 
cliffs.  Some  of  them,  coming  straight  from  the  sea, 
make  at  once  for  the  heights,  and  climb  laboriously 
from  ledge  to  ledge.  Do  they  meet  their  last  year's 
partners  at  the  summit?  Dr.  Levick  found  a 
colony  at  the  very  top,  about  700  feet  above  the 
sea,  a  site  which  involves  prodigious  toil.  "  During 
the  whole  of  the  time  when  they  are  rearing  their 


A  PECULIAR  PEOPLE  13 

young,  these  mountaineers  must  make  several 
journeys  during  each  twenty- four  hours,  to  carry 
their  enormous  bellyfuls  of  Euphausia  all  the 
way  from  the  sea  to  their  young  on  the  nests — a 
weary  climb  for  their  little  legs  and  bulky  bodies, 
each  upward  journey  taking  them  some  two  hours 
of  strenuous  climbing." 

Not  until  the  eggs  have  been  laid  does  either 
parent  go  to  feed.  Then  one  of  them  goes  off  to  the 
water  and  stays  away  in  many  cases  for  seven  to  ten 
days,  after  which  it  returns  and  gives  the  other  its 
leave.  The  shortest  period  of  total  abstinence  from 
food  is  about  eighteen  days,  and  the  longest  about 
twenty-eight  days — a  good  instance  of  the  parental 
sacrifice  so  characteristic  of  many  of  the  finest 
expressions  of  animal  life.  When  the  chicks  are 
hatched,  the  parents  relieve  one  another  at  frequent 
intervals,  and  their  shape,  always  quaint,  becomes 
grotesque  when  they  return  so  heavily  laden  with 
crustaceans  that  they  have  to  lean  back  to  keep 
their  balance.  Sometimes  they  try  to  carry  so 
much  that  they  lose  it  all.  The  chicks  feed,  as 
young  cormorants  do,  by  thrusting  their  head  into 
the  parental  gullet.  When  the  hen  is  sitting,  nothing, 
not  even  a  wrangle  with  her  next-door  neighbor, 
will  induce  her  to  move  until  her  turn  comes;  but 
the  cocks  are  easily  led  astray  by  their  combative- 
ness,  and  often  do  a  lot  of  harm  in  the  crowded 
rookery  in  spite  of  the  protests  of  adjacent  birds 
who  are  seen  trying  to  make  peace. 

In  the  water  the  Adelie  has  but  one  enemy,  the 


14  SECRETS  OF  ANIMAL  LIFE 

sea-leopard,  and  out  of  water  none  that  is  deadly 
save  man.  The  penguins  take  no  particular  notice 
of  the  killer-whales,  but  they  have  a  mortal  terror 
of  the  sea-leopards,  who  sometimes  swallow  them 
whole.  These  voracious  Pinnipedes  often  lurk 
below  the  ledge  from  which  the  penguins  dive, 
and  Dr.  Levick  gives  us  a  glimpse  of  another  side 
of  penguin  nature  when  he  tells  of  the  tricks  the 
birds  play  to  get  one  of  their  number  to  be  the  first 
to  go  into  the  water.  Apart  from  the  sea-leopards, 
man,  and  one  another,  the  adult  penguins  live  at 
peace,  but  terrible  damage  is  often  done  at  thaw- 
time  by  falling  boulders  and  land-slides.  Some- 
times, too,  crowds  of  nesting  birds  are  buried  in 
snow-drifts  which  are  especially  serious  when  they 
freeze  on  the  surface.  But  even  then  the  tough 
creatures  can  survive  for  many  weeks  within  little 
chambers  thawed  by  the  warmth  of  their  bodies, 
and  provided  with  breathing-holes  through  which 
they  thrust  their  heads.  On  the  whole,  the  adult 
birds  are  very  safe,  but  among  the  eggs  and  the 
young  the  mortality  is  high,  for  which  the  voracious 
skuas  and  the  recklessly  combative  or  even  vicious 
cocks  are  largely  to  blame. 

There  is  a  lighter  side  to  the  life  of  the  penguins, 
for  they  have  developed  a  taste  for  certain  primitive 
games  which  they  play  on  the  sea-ice  on  their  way 
to  and  from  their  bathe.  There  is  the  diving,  in 
which  the  succession  is  so  rapid  "  as  to  have  the 
appearance  of  a  lot  of  shot  poured  out  of  a  bottle 
into  the  water";  there  is  the  "porpoising,"  the 


A  PECULIAR  PEOPLE  15 

leaping  out  of  the  water,  and  the  game  of  "touch 
last"  on  the  sea-ice.  A  favorite  ploy  was  to 
board  an  ice-floe  till  it  would  hold  no  more,  and  get 
carried  by  the  tide  to  the  lower  end  of  the  rookery, 
where  every  bird  would  suddenly  jump  off  and  swim 
back  against  the  stream  to  catch  a  fresh  floe  and 
get  another  ride  down.  To  find  the  time  for  all  this 
fun  without  leaving  the  chicks  to  perish,  a  strange 
device  has  been  evolved.  The  parents  "pool  their 
offspring"  in  groups  which  are  left  in  charge  of 
a  few  conscientious  persons  (there  is  great  indi- 
viduality among  the  members  of  the  penguinery) 
who  ward  off  the  skuas  and  keep,  or  try  to  keep, 
the  chicks  from  straying.  The  holidaying  parents 
bring  food  at  intervals,  when  their  conscience  smites 
them — and  they  remain  faithful  to  their  own 
creches.  On  the  whole,  the  Adelie's  lot  appears  to 
be  a  happy  one,  and  we  read  with  pleasure  of  the 
"  ecstatic "  attitude  which  they  assume,  and  the 
weird  "chant  de  satisfaction"  which  they  utter 
when  all  is  well  with  their  world. 

One  other  picture  is  surely  unique  in  the  annals 
of  natural  history.  It  was  a  sort  of  drilling  on 
the  ice,  a  congregating  of  thousands,  and  the 
execution  of  ordered  movements  for  hours  on  end. 
Dr.  Levick's  interpretation  is  probably  correct,  that 
although  what  he  saw  was  not  directly  connected 
with  migration,  it  may  represent  an  echo  of  a  by- 
gone habit  of  massing  together  in  large  numbers 
before  the  autumnal  journey  northwards.  The 
journey  is,  of  course,  still  undertaken,  but  little 


16         SECRETS  OF  ANIMAL  LIFE 

is  known  of  it,  for  the  winter-quarters  of  the  Adelie 
penguins  after  they  leave  the  Antarctic  shores  are 
wrapped  in  blizzard  and  mist,  though  they  prob- 
ably lie  near  the  northernmost  limit  of  the  pack-ice 
in  the  far  southern  seas. 


Ill 

RAIDS  OF  THE  AMAZON  ANTS 

FOR  more  than  forty  years  zoology  has  been 
continuously  enriched  by  the  observations  of 
Professor  Carlo  Emery,  an  Italian  naturalist,  who 
has  grown  old  in  the  service  of  entomology  and  in 
the  study  of  ants  in  particular.  One  of  his  recent 
papers  (1916)  reports  on  fresh  investigations  of 
the  European  Amazon  ant,  one  of  the  handsomest 
and  most  bewildering  of  pismires.  To  appreciate 
Emery's  advance  we  must  recall  the  main  facts 
of  a  strange  story.  Transitory  mixed  colonies  of 
two  species  of  ants  are  not  very  uncommon;  they 
lead  on  to  cases  like  the  blood-red  ant,  Formica 
sanguined,  a  gifted,  belligerent  creature  which 
usually  makes  slaves  of  the  workers  of  other  species, 
but  can  thrive  well  enough  without  them  if  it 
chooses.  Very  different  from  these  sanguinary 
ants,  as  they  may  be  called,  are  the  degenerate 
slave-holders  and  the  social  parasites,  which  are 
altogether  dependent  on  their  slaves  or  hosts.  But 
between  the  degenerate  forms  which  have  sur- 
rendered independence  for  ease,  and  the  sanguinaries 
which  can  be  independent  if  they  will,  are  the 
Amazons.  They  cannot  live  without  slaves,  and 

17 


18  SECRETS  OF  ANIMAL  LIFE 

yet  they  have  not  so  far  become  in  any  marked 
way  degenerate. 

The  European  species,  Polyergus  rujescens,  was 
first  recognized  as  a  slave-owner  by  the  Swiss 
entomologist  Pierre  Huber  (in  1810) ;  his  fine  ob- 
servations were  extended  by  his  fellow-countryman 
Auguste  Forel,  also  working  on  the  shores  of  the 
Lake  of  Geneva;  and  now  Professor  Emery  has 
added  to  the  story.  The  American  Amazons 
have  been  best  studied  by  Professor  W.  M. 
Wheeler.1  The  Amazon  workers  and  queens  have 
jaws  well-suited  for  killing  but  ill-suited  for  burrow- 
ing, or  obtaining  food,  or  tending  the  young.  They 
cannot  dig,  but  to  beg  and  to  steal  they  are  not 
ashamed.  They  are  militarist  aristocrats  who  will 
not  soil  their  hands  with  toil.  As  Professor  Wheeler 
puts  it :  "  While  in  the  home  nest  they  sit  about  in 
stolid  idleness  or  pass  the  long  hours  begging  the 
slaves  for  food  or  cleaning  themselves  and  burnish- 
ing their  ruddy  armor,  but  when  outside  the  nest 
on  one  of  their  predatory  expeditions  they  display 
a  dazzling  courage  and  capacity  for  concerted  action 
compared  with  which  the  raids  of  the  'sanguinary 
ants'  resemble  the  clumsy  efforts  of  a  lot  of  un- 
trained militia."  But  they  have  paid  for  their 
combative  accomplishments  dearly,  for  they  cannot 
live  without  their  auxiliaries  or  hosts  or  slaves. 
We  use  all  these  words  because  no  one  of  them 
alone  will  serve  to  denote  the  strange  association. 

1  See  his  fascinating  and  reliable  book — Ants  (Columbia 
University  Series). 


RAIDS  OF  THE  AMAZON  ANTS         19 

It  will  be  borne  in  mind  that,  apart  from  the  repro- 
ductive "  queens,"  the  actively  militarist  creatures 
we  are  concerned  with  here  are  all  non-reproductive 
females,  the  so-called  "workers." 

A  notable  step  was  taken  by  Emery  in  1908  and 
1909 — namely,  the  starting  of  an  experimental 
nest.  He  introduced  a  fertilized  queen  Amazon 
into  one  of  M.  Charles  Janet's  formicaria  which 
was  inhabited  by  a  colony  of  Brown  Ants.  One  of 
the  first  events  was  that  the  Amazon  queen  slew 
the  Brown  queen,  and  was  enthroned  in  her  stead. 
In  the  course  of  two  years — we  must  omit  the 
details — Professor  Emery  had  a  flourishing  colony, 
consisting  of  Amazons  who  had  never  been  outside 
the  walls  and  a  serviceable  number  of  Brown  slaves. 
The  importance  of  the  experiment  is  evidently  that 
it  shows  how  a  mixed  colony  of  Amazons  and 
auxiliaries  may  arise.  In  the  early  days  of  the 
colony  in  question  the  slaves  treated  the  Amazons 
as  if  they  were  pets;  they  would  not  let  them 
even  take  an  airing  in  the  illumined  part  of  the 
formicarium,  and  if  one  escaped  it  was  quickly 
brought  indoors  again.  By  and  by,  however, 
the  Amazons  became  more  numerous  and  fidgety 
("remuantes  "),  and  one  after  another  set  out  on 
scouting  expeditions.  When  we  remember  that 
they  were  exploring  a  new  world  we  cannot 
but  be  amazed  that  a  solitary  scout,  discovering 
a  nest  of  Brown  Ants,  should  forthwith  enter, 
attack  the  crowd  of  workers,  seize  a  cocoon,  and 
carry  it  home.  Instinct  must  have  its  way. 


20  SECRETS  OF  ANIMAL  LIFE 

In  the  summer  of  1911,  after  scouting  had  con- 
tinued for  some  time,  Emery  noticed  one  afternoon 
a  growing  excitement,  and  the  issue  of  a  platoon 
of  sixty  Amazons.  But  they  only  went  a  couple 
of  yards  or  so,  and  then  returned.  About  an  hour 
afterwards  there  was  another  sally  which  made 
straight  for  a  colony  of  Brown  Ants  and  came  back 
laden  with  prisoners  (babies  and  children  as  usual). 
Going  and  coming  several  times  the  Amazons  got 
over  450  prisoners  that  evening.  In  1912  and  1913, 
Emery  continued  working  with  his  artificial  nest 
which  he  shifted  hither  and  thither  (a  method 
likely  to  be  very  useful  in  tackling  myrmeco- 
logical  problems),  and  he  confirmed  Forel's  descrip- 
tion of  the  rapidity  and  precision  of  some  of  the 
predatory  raids.  This  probably  depends  in  part 
on  the  previous  reconnoitering,  and  it  seems  likely 
enough  that  a  scout  who  has  discovered  a  suitable 
object  of  pillage  may  give  the  direction  to  the 
raiders,  if  it  does  not  actually  lead  the  way.  In 
one  instance,  reported  by  Forel,  the  nest  to  be 
pillaged  was  at  a  distance  of  over  16  feet,  but  the 
Amazon  army  went  straight  for  the  goal. 

A  most  extraordinary  case  was  long  ago  reported 
by  Ebrard.  One  forenoon  he  took  home  a  nest  of 
common  ants  and  their  cocoons,  inclosed  in  a 
carefully  tied  handkerchief,  and  deposited  it  in  a 
room  on  the  second  story,  meaning  to  give  the 
warblers  in  his  aviary  a  treat.  In  the  course  of  the 
afternoon,  on  returning  from  a  walk,  he  found  his 
servants  in  a  state  of  great  excitement,  for  the  house 


RAIDS  OF  THE  AMAZON  ANTS        21 

had  been  invaded  by  legions  of  Amazon  ants  which 
had  made  their  way  upstairs  and  pillaged  the 
precious  handkerchief,  carrying  off  the  cocoons 
meant  for  the  singing  birds.  The  probability  is 
that  a  wandering  Amazon  scout  had  discovered 
the  treasure  in  the  napkin  and  had  carried  the  news 
to  headquarters.  Hence  the  raid — prompt,  precise, 
and  resolute ;  and  our  admiration  for  the  Amazons 
grows. 

In  one  of  Emery's  experiments,  the  artificial 
nest  was  placed  in  a  walled  court  with  no  trace  of 
desirable  objects  of  pillage.  Yet  there  were  re- 
peated expeditions.  Were  these  prompted  by  the 
victims  of  illusion,  who  "believed  they  had  dis- 
covered ant  nests  where  none  existed"?  This 
being  absurd,  Emery  would  have  us  note  that  his 
particular  colony  had  been  transplanted  into  a 
terra  incognita,  where,  naturally  enough  (are  we 
not  poignantly  aware  of  analogous  cases  in  human 
warfare?),  the  expeditions  were  a  little  fatuous. 
In  an  established  Amazon  colony,  however,  mastery 
of  the  environment  is  soon  attained,  and  the  raids 
are  swift  and  sure.  We  do  not  hold  up  Amazon 
ants  as  ideals  for  mankind — or  should  we  not  say 
womankind  in  a  case  like  this? — but  we  confess 
to  some  admiration  for  their  promptness,  precision, 
courage — and  success.  It  is  rather  a  despicable 
business  this  kidnapping  of  children  for  slaves — 
but  the  Amazons  do  it  well.  In  one  raid  which 
began  about  five  o'clock  in  the  afternoon,  over  a 
thousand  prisoners  were  taken  before  quarter  to 


22  SECRETS  OF  ANIMAL  LIFE 

seven,  when  Professor  Emery's  son  stopped  count- 
ing. It  seems  likely  that  the  Amazons  are  moved 
by  an  instinctive  restlessness,  which  becomes  peri- 
odically irrepressible,  and  leads  to  the  impetuous 
raids,  which,  by  the  way,  are  almost  invariably 
confined  to  the  afternoon. 

In  1914  the  veteran  observer  made  a  study  of  a 
flitting  from  one  nest  to  another.  On  the  first 
afternoon  the  Amazons  were  seen  carrying  their 
slaves,  sometimes  in  contradictory  fashion  in 
opposite  directions;  but  after  that  the  slaves  did 
most  of  the  work  of  transporting  the  young,  and 
even  carried  their  mistresses.  On  another  occasion 
Emery  saw  an  unusual  sight,  perhaps  a  mutiny, 
but  more  probably  a  madness.  Several  slaves 
attacked  an  Amazon  and  began  to  pull  her  about; 
she  slew  two  of  them  forthwith,  but  was  soon 
afterwards  attacked  by  another  Amazon,  and  there 
ensued  a  quarrel  fatal  to  both.  Next  day  the  slaves 
were  seen  carrying  off  the  two  bodies. 

Like  Huber  and  Forel  before  him,  Emery  puzzled 
over  the  resistance  that  the  auxiliaries  often  offer 
to  the  issue  of  an  expedition  of  Amazons.  Forel 
suggested  that  the  young  auxiliaries,  brought  in 
from  outside,  have  to  become  accustomed  to  the 
strange  proceedings  before  they  can  acquiesce  in 
raids  as  part  of  the  order  of  the  day.  Emery 
suggests,  however,  that  there  is  something  subtler — 
namely,  "  a  myrmecophilous  relation  " — that  the 
servants  hold  their  mistresses  as  something  like 
wayward  pets.  He  admits,  however,  that  in  the 


RAIDS  OF  THE  AMAZON  ANTS         23 

course  of  the  summer  this  relation  wears  rather 
thin.  One  is  tempted  to  recall  the  way  in  which 
the  servants  carry  their  strayed  mistresses  home, 
or  the  influence  of  evil  communications  seen  in  the 
fierceness  which  sometimes  infects  the  timid  Brown 
Ants,  and  leads  them  .to  share  in  the  slave-making. 
But  our  last  note  on  this  weird  under-world — 
full  of  warning  and  caricature — must  be  the  sad 
question  whether  these  intrepid  Amazons  are 
doomed  in  the  course  of  evolution  to  the  degenera- 
tion which  has  beset  other  emmets  who  have  played 
with  their  independence. 


IV 
SOCIAL  LIFE  OF  WASPS 

SURELY  in  the  jetsam  of  the  autumn's  ebb- 
tide there  is  no  more  eloquent  item  than  that 
wasps*  nest  in  the  gooseberry  bush — empty  since 
the  morning  frosts  of  early  September.  Most 
people  hail  "the  last  of  the  wasps"  with  consider- 
able satisfaction,  and  even  their  champions  must 
admit  that  there  are  limits  to  their  relevancy; 
yet  we  never  see  their  autumnal  dying-off  with- 
out giving  them  our  admiration.  Laying  aside  a 
colossally  absurd  prejudice,  who  can  fail  to  ap- 
preciate the  workmanship  of  that  familiar  hanging 
edifice,  often  as  big  as  one's  head,  an  elegant  house 
of  paper,  fabricated  from  salivated  shavings  planed 
from  fences  and  disbarked  branches?  There  we 
see  story  hung  from  story,  with  perfect  economy 
of  space  and  security  of  ventilation;  a  compacted 
framework  of  hundreds  of  cradles  rivaling  the 
honeycomb  of  hive-bees;  and  outside  it  all  a  series 
of  rainproof  and  windproof  envelopes. 

Some  biologists  have  said  that  animals  use  matter 
constructively  inside  their  bodies,  whereas  man 
brings  matter  into  his  service  extra-corporeally. 
This  is  going  much  too  far,  however,  for  there  are 
many  of  the  more  adventurous  animal  types — but 

M 


SOCIAL  LIFE  OF  WASPS  25 

for  whose  pioneering  Man  might  never  have  been 
— that  undoubtedly  bend  matter  to  their  will  out- 
side their  bodies.  Think  of  the  nest-builders 
like  the  house-martins  and  weaver-birds,  the  net- 
makers  like  the  spiders,  the  home-makers  like  the 
termites  and  beavers,  the  trap-contrivers  like  the 
larval  ant-lions,  the  store-accumulators  like  the 
bees,  the  bed-makers  like  the  anthropoid  apes,  and 
so  on,  not  forgetting,  as  a  sort  of  climax,  the  honey- 
mooning bower-birds.  It  may  not  be  "art"  that 
these  creatures  show,  but  there  is  no  doubt  as  to 
their  triumphantly  skilful  use  of  materials.  Samuel 
Butler  declared  that  animals  have  tools  which  are 
part  of  them  and  cannot  be  laid  down;  whereas 
man  has  limbs  which  are  apart  from  him  and 
detachable.  Which  is,  in  the  main,  good  sense. 
But  whether  a  living  creature  planes  with  a  tool 
or  with  its  mandibles,  it  planes;  and  that  requires 
skill.  And  the  planing  is  only  the  first  step  toward 
the  wasp's  nest,  which,  taken  objectively,  is  a  far 
finer  thing  than  many  a  human  erection  which 
entitles  its  tenant  to  a  vote. 

And  it  is  not  only  the  architecture  of  wasps  that 
commands  our  admiration;  there  is  the  coherence 
of  the  large  family  or  community,  sometimes 
numbering  several  thousand  members;  there  is 
the  creature's  strength,  displayed  in  lifting  a  drone- 
fly  half  its  own  size  off  the  ground  and  carrying 
it  through  the  air;  there  is  contrivance  in  cutting 
off  the  wings  of  a  big  insect  before  it  tries  to 
transport  it  through  the  air;  there  is  the  uncanny 


26  SECRETS  OF  ANIMAL  LIFE 

power  of  flying  backwards  in  front  of  one's  bicycle 
for  a  quarter  of  a  mile  at  a  time;  there  is  the 
consummate  efficiency  (incalculably  beneficent  from 
man's  point  of  view)  in  destroying  in  a  great  variety 
of  ways  large  numbers  of  injurious  insects — for 
wasps  are  carnivores  and  scavengers  of  big  appetite, 
as  well  as  the  honey-suckers,  fruit-eaters,  and  jam- 
thieves  we  all  know  them  to  be. 

But,  tearing  ourselves  away  from  these  familiar 
wonders,  we  wish  to  direct  attention  to  a  quaint 
piece  of  domestic  economy  which  Dr.  Roubaud  has 
recently  discovered  among  African  wasps.  These 
know  no  winter  or  interruption  in  their  year,  and 
they  throw  fresh  light  on  species  like  ours  which 
are  severely  punctuated  by  northern  seasons.  For 
it  is  well  known  that  of  the  great  summer  com- 
munity of  wasps  only  the  young  fertilized  queens 
survive  the  winter.  They  have  sought  out  sheltered 
nooks,  under  thatch  and  the  like,  where,  fixed  by 
their  jaws,  and  occupying  a  position  quaintly  like 
that  which  they  had  as  pupae  within  their  cradles, 
they  lie  asleep  till  the  spring. 

Among  bees  and  wasps  there  has  been  social 
evolution  on  a  primarily  instinctive  and  secondarily 
intelligent  basis — rookeries  and  the  like  being  on 
a  primarily  intelligent  and  secondarily  instinctive 
basis ;  our  evolution  being  on  a  vaguely  instinctive, 
primarily  intelligent,  and  occasionally  rational 
basis.  There  are  many  solitary  wasps  and  solitary 
bees,  and  there  are  many  grades  of  sociality,  or 
whatever  it  be  called,  between  the  solitary  life  and 


SOCIAL  LIFE  OF  WASPS  27 

that  of  the  bee-hive  and  the  wasps'  "bike."  In 
the  social  evolution  of  these  Hymenoptera  there 
have  evidently  been  two  divergent  lines — one 
towards  honey-storing  and  the  other  towards 
predatory  alimentation.  The  honey-storing  regime 
has  its  climax  in  hive-bees,  with  many  gradations 
leading  up  to  that  pitch  of  perfection;  and  down 
at  the  base  of  this  line  it  seems  that  we  must,  for 
anatomical  reasons,  include  the  solitary  digger 
wasps  (Sphegidae),  which  store  paralyzed  insects 
and  spiders  for  their  larvae.  The  predatory  regime 
has  its  climax  in  some  of  tropical  social  wasps, 
while  many  others,  not  less  predatory,  called 
Eumenids  and  Pompilids,  remain  at  the  solitary 
level.  And  just  as  the  predatory  digger-wasps 
or  Sphex-wasps,  mentioned  a  moment  ago,  seem 
to  go  with  the  bees,  so  there  is  a  family  of  "honey- 
wasps  "  (Masarids)  which  go  with  the  main  body 
of  the  wasps,  though  they  do  not  practise  the 
paralyzing  device,  and  are,  indeed,  vegetarian,  both 
as  larvae  and  as  adults.  The  predatory  regime 
appears  to  be  the  more  primitive  of  the  two,  and 
it  has  been  suggested  that  honey-storing  was  re- 
sorted to  by  types  whose  poison  was  not  suited 
for  the  preservation  of  animal  food.  In  any  case, 
the  broad  fact  is  that  social  organizations  have 
been  evolved  on  the  hive-bee  line  of  storing  honey 
and  on  the  social- wasp  line  of  supplies  of  fresh 
meat.  There  has  been  an  interesting  dichotomy  of 
vegetarians  and  carnivores! 

According  to  Dr.  Roubaud,  the  first  chapter  in 


28  SECRETS  OF  ANIMAL  LIFE 

the  social  evolution  of  wasps  is  illustrated  by  some 
of  the  Diggers  and  Pompilids,  where  the  mother 
makes  for  her  larvae  a  larder  of  paralyzed  victims, 
but  has  no  further  commerce  with  her  brood.  She 
quickly  makes  a  store  of  preserved  (indeed,  living) 
flesh  and  has  done  with  it.  The  second  chapter 
is  seen  in  some  African  Eumenid-wasps,  in  which 
the  mother  brings  freshly-paralyzed  victims  from 
day  to  day  as  her  hatched  larva  has  need  of  them. 
There  is  more  of  a  personal  touch  here,  for  the 
mother  comes  into  intimate  relations  with  her  off- 
spring, and  seems  to  know  it  as  hers.  The 
third  chapter  shows  an  abandonment  of  the  paralyz- 
ing device,  the  poison  not  being  used  except  in 
killing  the  naturally  recalcitrant  victims.  The 
prey  is  more  or  less  masticated  into  pap,  the  mother 
retaining  a  tithe  for  herself,  and  the  result  is  laid 
beside  the  larva,  whose  mouth,  it  is  very  interest- 
ing to  notice,  has  ceased  to  have  much  power  of 
chewing. 

But  some  very  curious  features  now  come  to 
light,  that  the  salivary  secretion  of  the  larva  be- 
comes greatly  exaggerated,  as  sometimes  happens 
in  man;  that  it  tends  to  overflow  at  the  mouth; 
and  that  it  is  for  the  mother  "  1'objet  d'une  recherche 
particuliere."  It  is  the  sop  that  keeps  the  mother- 
wasp  self-forgetful,  corresponding  to  the  look  in  a 
baby's  eyes  that  keeps  a  human  mother  from  utter 
weariness.  The  nurture  of  a  single  larva,  distributed 
over  a  considerable  time,  leaves  the  mother-wasp 
with  the  gift  of  leisure,  and  there  are  gradations 


SOCIAL  LIFE  OF  WASPS  29 

showing  how  this  is  utilized  in  increasing  the 
family.  The  simultaneous  nurture  of  a  number  of 
offspring  means  more  work,  but  it  also  means  more 
salivary  juice,  which  is  an  elixir  of  life  to  the 
mother-wasps.  Roubaud's  theory,  perhaps  an  ex- 
aggeration of  a  truth,  is  that  the  attractiveness  of 
this  secretion  has  been  the  principal  factor  in  the 
social  evolution  of  wasps.  The  nest  has  for  its 
"end,"  whatever  that  may  mean,  "a  rational  ex- 
ploitation of  the  larvae,"  and  its  regime  is  such  that 
a  constant  supply  of  newborn  wasp-babies  is  kept  up. 
For  only  the  young  larvae  secrete  the  elixir.  A 
system  of  nutritive  exchange  (cecotrophobiosis  it  is 
quaintly  called)  has  been  established,  mothers  and 
children  playing  into  one  another's  hands.  Just  as 
tailor-ants  use  their  children  as  needle-and-thread,  so 
these  wasp-mothers  obtain  from  their  offspring 
those  luxuries  which  for  animal  as  well  as  for  man 
often  mean  more  than  necessaries. 

It  is  hopelessly  difficult  for  man  to  get  mentally 
into  touch  with  wasps,  for  our  lives  and  theirs  are 
run  on  quite  different  methods,  which  Sir  Ray 
Lankester  has  spoken  of  as  the  "little-brain"  and 
the  "big-brain,"  the  instinctive  and  the  intelligent, 
lines  of  evolution.  Yet  we  venture  to  think  that 
further  research  will  show  that  Dr.  Roubaud's 
theory  is  not  altogether  sound.  We  would  suggest 
that  what  he  exaggerates  into  the  main  motive  is 
only  the  sop,  the  douceur,  the  encouragement,  which, 
organism  being  what  it  is,  remains  even  unto  the 
end  an  exceedingly  desirable  stimulus  of  altruism. 


30  SECRETS  OF  ANIMAL  LIFE 

There  are,  as  we  have  seen,  thoroughly  solitary 
wasps,  and  there  are  those  that  form  a  community. 
Between  the  two  there  are  wasps  that  build  their 
nests  in  close  proximity — each  making  its  own, 
however — and  there  are  wasps  that  hibernate  in 
companies.  That  this  gregariousness  may  be  of 
protective  value  is  practically  certain,  but  it  is  very 
unlikely  that  the  social  state  was  reached  along 
this  line.  Roubaud's  view  is  that  the  social  life  had 
its  beginnings  in  "filial  associations/'  Daughters 
were  hatched  in  the  nest  while  their  mother  was 
still  about;  if  the  stores  were  abundant  and  if 
there  were  plenty  of  younger  sisters  to  supply  elixir, 
then  it  would  be  easier  for  the  elder  daughters  to 
see  their  way  to  remain  at  home  and  collaborate 
with  their  mother  in  the  nurtural  task.  As  Verhoeff 
also  has  maintained,  the  wasp-community  is  not 
the  outcome  of  grouping,  but  of  filial  association, 
and  Roubaud's  addition  (toned  down  a  little)  is  that 
the  elixir  makes  the  corporate  life  run  smoothly. 
We  must  remember  that  we  are  dealing  with 
arrangements  of  prodigious  antiquity,  for  wasp 
societies  date  back  to  Oligocene  ages  (perhaps  two 
million  years  ago),  and  are  thus  much  older  than 
human  societies.  There  has  been  plenty  of  time  for 
experimenting. 

To  those  who  would  puzzle  over  origins  the  case 
of  a  primitive  social  wasp  called  Belonogaster  is 
peculiarly  instructive.  In  hard  times  the  Belono- 
gaster queen  reverts  to  the  solitary  regime  and 
brings  up  only  one  larva  at  a  time.  When  things 


SOCIAL  LIFE  OF  WASPS  31 

are  going  better,  yet  not  too  well,  the  young  females 
remaining  at  home  have  to  work  so  hard  and  on 
such  scanty  food  that  their  reproductivity  is 
hindered.  Although  fertilized  they  are  slow  to  lay. 
They  continue  helping  their  mother — and  they  thus 
almost  originate  a  caste  of  "workers"!  Such 
polygynous  or  many-queened  communities  are 
restricted  to  warm  countries  where  nesting  continues 
all  the  year  round.  In  cold  countries  the  com- 
munities are  always  monogynous,  i.e.  there  is  but 
one  functional  queen.  The  workers  remain  more  or 
less  completely  sterile.  The  queens  of  next  year 
are  the  young  females  hatched  near  the  end  of  the 
season,  which,  as  we  have  already  mentioned,  spend 
the  winter  in  safe  retreats.  It  is  interesting  to 
think  that  the  establishment  of  the  monogynous 
society  was  probably  Northern  and  relatively  recent, 
being  imposed  upon  wasps  by  climatic  conditions. 
It  is  interesting  also,  though  very  grim,  to  recognize 
that  the  general  massacre  of  the  wasp-larvae  in 
autumn,  when  further  nurture  is  hopeless,  is  not 
incongruent  with  the  "  cecotrophobiosis."  For  the 
young  creatures  that  can  no  longer  furnish  elixir 
are  not  to  be  wasted.  They  are  eaten  up,  and  it  is 
on  the  strength  of  them  that  the  wintering  young 
queens  are  able  to  sleep  for  many  days  without 
food,  and  to  begin  the  cycle  again  next  spring. 
It  is  altogether  a  very  economical  kind  of  domestic 
economy. 


K 

THE  CAWING  OF  ROOKS 

THE  cawing  of  rooks  is  one  of  the  characteristic 
sounds  of  spring,  and  it  is  one  of  good  cheer. 
There  is  vigor  in  it  and  exultation  in  the  victory 
of  life  over  materials,  for  the  building  of  big  nests 
on  the  delicate  branches  of  the  swaying  tree-tops  is 
a  real  achievement.  The  cawing  is  the  voice  of 
strong-willed  mates  and  of  jealous  parents.  It  is 
more  than  the  babel  of  a  crowd;  it  is  the  vocifera- 
tion of  big-brained  creatures  that  have  got  past 
simple  gregariousness,  and  live  in  what  is  more  than 
the  adumbration  of  a  society.  We  like  it  too  because 
it  is  one  of  the  earliest  awakening  voices  of  spring. 
As  the  child's  poem  says  : 

Buds  of  green  on  branch  and  stem. 

Glisten  in  the  morning  sun. 
For  the  crows  have  wakened  them, 

And  they  open  one  by  one. 

We  have  been  listening  these  days  to  the  cawing 
of  the  rooks,  and  they  certainly  have  a  considerable 
vocabulary.  There  is  probably  no  language  in  the 
strict  sense — man  has  a  monopoly  of  that;  but  the 
rooks  have  words  just  as  dogs  have,  definite  uttered 
sounds  which  have  definite  meanings.  Words  are 

32 


THE  CAWING  OF  ROOKS  33 

uttered  when  we  move  suddenly  beneath  the  trees, 
and  other  words  are  uttered  when  a  bird  intrudes 
on  the  precincts  of  a  neighbor's  nest;  there  is  a 
word  when  the  rook  sinks  down  upon  the  nest, 
and  another  word  when  it  flies  clear  of  the  rookery 
and  makes  for  the  fields.  What  danger-signals, 
what  scoldings,  what  satisfaction,  what  exultation, 
what  reproaches,  what  encouragements  do  we  not 
hear?  There  is  no  doubt  that  the  members  of  the 
crow  family  have  fine  brains  and  a  notable  power 
of  vocalization,  which  training,  as  in  jackdaws  and 
ravens,  may  develop  to  a  remarkable  degree;  the 
finely  innervated  musculature  of  the  voice-box 
(or  syrinx)  is  more  highly  differentiated  than  in  the 
master-songsters,  such  as  blackbird  and  mavis, 
Experts  tell  us  that  the  rook  has  between  thirty 
and  forty  notes,  which  can  be  intricately  combined. 
This  may  be  best  appreciated  at  the  roosting-place 
after  the  busy  breeding  season  is  over  and  summer 
has  come.  "  A  marvelous  medley/'  said  Mr. 
Edmond  Selous  in  his  delightful  Bird  W  etchings, 
"a  wonderful  hoarse  harmony.  Here  are  shoutings 
of  triumph,  chatterings  of  joy,  deep  trills  of  con- 
tentment, hoarse  yells  of  derision,  deep  guttural 
indignations,  moanings,  groanings,  tauntings,  re- 
monstrances, clicks,  squeaks,  sobs,  cachinnations, 
and  the  whole  a  most  musical  murmur.  Loud,  but 
a  murmur,  a  wild,  noisy,  clamorous  murmur;  but 
sinking  now,  softening — a  lullaby. 

I  never  heard 
So  musical  a  discord,  such  sweet  thunder." 


34  SECRETS  OF  ANIMAL  LIFE 

We  shall  appreciate  the  cawing  of  the  rooks 
better  if  we  inquire  into  the  story  of  "the  black 
republic  in  the  elms."  It  is  in  February  that  the 
rooks'  spring  begins,  for  then  there  is  the  courting. 
This  takes  place,  not  once  in  a  lifetime,  but  every 
spring,  between  mates  who  have  been  married  for 
years.  For  they  seem  to  be  monogamous.  The 
cock-bird  struts  and  bows  before  the  hen,  and 
spreads  his  wings  and  tail.  Moreover,  as  Gilbert 
White  observed  long  ago,  "rooks,  in  the  breeding 
season,  attempt  sometimes,  in  the  gaiety  of  their 
hearts,  to  sing,  but  with  no  great  success."  It  should 
be  noted,  however,  that  the  singing,  the  bowing,  and 
the  tail-spreading  are  not  restricted  to  the  time  of 
courtship,  but  may  be  indulged  in  at  any  time  of 
excitement  or  jollity.  Very  interesting  is  Mr.  F.  B. 
Kirkman's  note  that  the  male  bird  sometimes 
brings  a  tit-bit  to  his  desired  mate,  which  she 
accepts  "  with  quivering  wings  and  stifled  thanks/' 
This  offering  of  love-gifts  occurs  sporadically 
among  animals.  It  is  part  of  the  ritual  which  aims 
at  working  up  the  female's  excitement,  and  in  the 
case  of  the  rook  and  many  other  birds  it  finds  a 
second  expression,  probably  the  primary  one,  when 
the  male  brings  food  to  the  nesting  female  and  to 
the  nestlings. 

The  courtship  is  followed,  early  in  March,  by  the 
preparation  of  the  nest.  An  old  nest  may  be  used 
over  again  after  a  thorough  spring-cleaning,  or  a 
fresh  one  may  be  built.  As  every  one  knows,  there 
is  a  good  deal  of  vigorous  quarreling  over  the 


THE  CAWING  OF  ROOKS  35 

possession  of  old  nests  or  of  new  sites;  and  up  to  a 
certain  point  there  is  stealing  of  materials.  This 
necessitates  one  bird  mounting  guard  while  the  mate 
collects,  the  division  of  labor  alternating.  Very 
remarkable  is  the  frequent  destruction  of  nests  that 
are  built  on  trees  in  the  outskirts  of  the  main  colony, 
as  if  the  sense  of  the  community  insisted  on  main- 
taining a  close  gregariousness.  One  tree  may  have 
to  carry  as  many  as  thirty  nests,  and  it  is  usual 
to  see  about  a  dozen.  The  nest  is  built  of  both 
dry  and  supple  twigs,  with  the  addition  of  earth 
and  clay,  and  the  inside  of  the  cup  is  made  soft 
with  grass  and  leaves,  hair  and  wool.  Among  the 
favorite  trees  are  ash,  elm,  beech,  Scots  fir,  and 
sycamore;  and  it  has  been  observed  over  and  over 
again  that  trees  which  betray  insecurity  are 
abandoned  by  the  rooks  even  after  the  nests  have 
been  built.  A  forsaken  tree  is  doomed,  and  this 
may  be  one  of  the  facts  that  have  given  basis  to 
some  of  the  superstitions  about  rooks. 

The  eggs  are  interesting  biologically  because  of 
their  great  variability  in  coloring — that  is  to  say, 
in  relatively  safe  nesting-places,  where  inconspicu- 
ousness  or  the  opposite  is  of  little  moment,  natural 
selection  has  imposed  no  limits  on  variation.  After 
the  laying,  towards  the  end  of  March,  the  mother 
bird  sits  close,  the  male  occasionally  relieving  her. 
There  is  no  more  returning  at  night  to  the 
communal  roosting-place,  which  is  usually  quite 
apart  from  the  rookery;  all  the  rooks  keep  vigil 
by  their  nests.  "  Relatively  safe,"  we  said,  for 


36  SECRETS  OF  ANIMAL  LIFE 

raids  by  carrion-crows  and  other  non-social  mem- 
bers of  the  family  Corvidae  are  common,  and  are 
sometimes  so  successful,  in  spite  of  the  strength  of 
unity,  that  the  rookery  is  deserted.  It  looks  as 
if  the  rooks  were  not  very  good  fighters,  though 
they  do  to  herons  what  carrion-crows,  hoodies,  and 
ravens  do  to  them.  Perhaps,  for  all  we  know,  it 
was  some  weakness  or  softness  of  character  that  led 
rooks  to  become  the  most  social  of  European  birds, 
for  apart  from  the  jackdaws,  which  are  so  often 
their  satellites,  the  other  members  of  the  race  to 
which  they  belong  are  solitaries  and  individualists. 
When  the  three  to  five  eggs  hatch,  the  parents 
have  to  be  busier  than  ever,  for  the  appetite  of  the 
young  birds  is  large.  Big  mouthfuls  of  grubs  and 
wireworms  and  the  like  are  brought  in,  making  a 
pouch-like  bulging  below  the  tongue;  and  at  this 
time  the  rooks  do  so  much  in  the  farmer's  interests 
that  we  should  not  be  too  hard  on  them  for  their 
depredations  at  other  times.  In  his  splendid 
British  Bird  Book  Mr.  Kirkman  quotes  from  Mr. 
Phil  Robinson  the  interesting  observation  that,  to 
begin  with,  the  male  bird  gives  the  food  only  to 
the  female,  who  passes  it  on  "  doubly  peptonized  to 
the  babies/'  and  that  later  on  both  parents  feed  the 
young.  "  But  it  is  most  extraordinary  to  notice 
how  the  young  accept  it  from  the  father  without 
any  demonstration,  sometimes  in  complete  silence, 
while  every  time  the  mother  approaches  they  lift 
up  their  voices  in  a  chorus  of  jubilation."  One 
would  like  to  hear  more  of  this  matter.  Every  one 


THE  CAWING  OF  ROOKS  37 

knows  that  the  rook  differs  from  the  crow  in  habit 
and  color,  in  the  loss  (after  the  first  year)  of  the 
feathers  round  the  back  of  the  beak,  and  so  on, 
but  it  is  instructive,  as  an  illustration  of  the  way  in 
which  specificity  penetrates  through  and  through 
a  creature,  that  while  the  inside  of  the  mouth  is 
always  pale  flesh-color  in  the  young  of  the  carrion- 
crow,  it  is  first  dark  flesh-color  and  then  slaty  in 
the  rook. 

In  many  parts  of  the  country  it  has  been  the 
custom  to  watch  the  rooks  with  particular  interest 
at  Easter-time,  for  from  the  manner  of  their  flight 
and  the  mood  of  their  cawing,  hints  of  coming  events 
were  believed  to  be  obtainable.  But  most  of  those 
who  watch  rooks  to-day  find  sufficient  interest 
in  their  present  and  past.  We  wish  one  of  those 
ornithologists  who  give  us  admirably  intimate 
studies  of  the  "Home  Life"  of  particular  birds 
would  make  a  detailed  critical  study  of  the  rook. 
There  are  so  many  points  of  great  interest.  Like 
many  creatures  well  endowed  with  brains,  rooks 
exhibit  what  must  be  called  play.  There  are  gambols 
and  sham-fights,  frolics  and  wild  chases,  in  which, 
curiously  enough,  jackdaws  and  lapwings  sometimes 
become  keenly  interested.  But  who  knows  the 
real  truth  about  rooks  posting  sentinels,  which  is  so 
often  alleged?  What  has  been  called  the  " ecclesias- 
tical air  "of  the  rook,  enhanced  by  the  white  about 
the  head,  gives  spice  to  an  apparent  humorousness, 
and  there  is  no  doubt  of  their  wisdom.  But  who 
knows  the  significance  of  the  vast  congregations 


36  SECRETS  OF  ANIMAL  LIFE 

that  are  sometimes  seen,  and  who  can  tell  us  if 
there  is  any  truth  at  all  in  the  alleged  "trials" 
of  individuals  who  have  defied  the  conventions  of 
the  community?  It  is  interesting  to  know  that  the 
rook  is  a  partial  migrant,  for  there  is  a  great  ebb  and 
flow  every  autumn  and  spring,  and  this  may  be  con- 
nected with  the  flitting  from  the  rookery  to  the 
roosting-place  that  we  see  in  September.  There 
may  be  far  over  a  thousand  nests  in  a  rookery 
and  the  same  site  may  be  used  for  more  than  a 
century;  and  it  is  very  interesting  to  have  statistics 
such  as  Mr.  Hugh  S.  Gladstone  has  given  for 
Dumfriesshire,  showing  how  old  rookeries  have 
waned  and  young  colonies  have  grown,  or  to  see  in 
the  inclosed  rookeries  of  towns  the  evidence  of  an 
almost  forgotten  urbanization  of  the  country.  But 
the  central  interest  is  in  the  rook's  reaching  forward 
to  a  communal  life  with  certain  conventions,  and  to 
the  crowded  nests  in  which  we  see  the  beginning  of 
a  continuous  social  heritage  of  objectively  enregis- 
tered  traditions. 


VI 
CUCKOO  PUZZLES 

FROM  various  places  we  hear  rumors  that 
the  number  of  birds  that  have  come  this 
year  (1916)  as  summer  visitors  is  below  the  normal, 
and,  considering  the  atmospheric  and  other  dis- 
turbances which  the  war  has  involved,  we  should 
not  be  surprised  if  it  were  true.  But  no  one  who 
had  the  good  fortune  to  be  near  Dalmally  and 
Loch  Awe  at  the  end  of  May  could  have  failed  to 
be  impressed  with  the  extraordinary  abundance 
of  cuckoos.  Whatever  was  true  of  other  summer 
visitors,  the  cuckoos,  at  any  rate,  were  present  in 
full  force.  They  seemed  to  be  everywhere — on  the 
hedges  by  the  wayside,  among  the  birch  bushes,  on 
poplar  trees  (whose  belated  buds  were  just  opening 
into  amber-colored  foliage),  and  on  the  telegraph 
wires  going  over  the  moor  to  Inveraray.  The  males 
were  shouting  excitedly  all  day  long — recalling 
Lyly's  "jolly  cuckoos/'  We  listened  to  him  at 
five  in  the  morning  telling  "  his  name  to  all  the 
hills,"  and  he  continued  to  call  far  into  the  night. 
In  the  midst  of  torrents  of  rain  we  heard  the 
"wandering  voice,"  "at  once  far  off  and  near"; 
and  all  through  a  storm,  when  the  thunder  rolled 
in  solemn  echoes  from  mountain  to  mountain  all 

39 


40  SECRETS  OF  ANIMAL  LIFE 

round  Ben  Lui,  we  heard  the  irrepressible  dissyllabic 
and  trisyllabic  call,  "Cuck-oo"  and  "  Cuck- 
cuck-oo."  One  fellow  seemed  to  call  thirteen  times 
in  succession,  unless  an  echo  or  a  rival  falsified  our 
counting ;  and  every  now  and  then  we  heard  the 
female's  curious  "water-bubbling"  laugh  (she  is 
not  known  to  say  "Cuck-oo"),  upon  which  there 
were  loud  answering  calls,  and  we  saw  a  rush  of  two 
or  three  males,  which  was  probably  followed  by  a 
scrimmage.  It  is  not  quite  certain  that  the  laugh- 
ing sound  is  confined  to  the  female.  It  must  not  be 
confused  with  a  remarkable  noise  often  made  by 
the  male  before  the  utterance  of  (f  cuck-cuck-oo" 
Mr.  Kirkman  compares  it  to  "  the  noise  that  would 
be  made  by  a  person  with  a  rasping  cough  trying 
not  to  laugh,  but  with  indifferent  success." 

One  of  the  many  cuckoo  puzzles  was  repeatedly 
before  us  on  our  week-end  holiday,  that  a  little 
bird  (like  a  hedge-sparrow  is  all  that  we  can  truth- 
fully say)  often  shadowed  the  cuckoo  on  its  flight, 
and  sometimes  flew  at  it  aggressively.  This  was 
seen  with  great  clearness  when  the  cuckoo  and 
the  little  bird  both  alighted  on  the  telegraph  wires. 
After  a  brief  pause  the  shadower  would  fly  up  in  the 
cuckoo's  face — a  pygmy  against  a  giant — whereupon 
the  "blessed  bird"  of  the  poets  would  change  its 
perch.  The  question  which  the  often-repeated  scene 
raised  was  whether  the  little  bird  was  a  re- 
sentful parent  in  whose  nest  the  cuckoo  had  been 
playing  its  well-known  trick.  Or  was  it  in  line 
with  that  mobbing  of  a  cuckoo  by  a  crowd  of  little 


CUCKOO  PUZZLES  41 

birds  which  we  have  seen  elsewhere,  which  is  often 
attributed  to  their  mistaking  the  cuckoo  for  a  hawk? 
There  remains  something  puzzling  here. 

Wordsworth  called  the  cuckoo  a  "mystery," 
and  its  behavior  certainly  presents  many  puzzles. 
The  central  one  is  the  mother's  evasion  of  brooding. 
As  is  well  known,  she  usually  lays  her  egg  on  the 
ground,  takes  it  in  her  beak  (sometimes  under  her 
tongue),  and  flies  with  it  to  the  previously-selected 
nest  of  another  bird.  Sometimes  when  the  nest 
is  suitable  she  lays  her  egg  directly  in  it,  but  this 
is  often  impossible.  All  is  done  quickly,  cautiously, 
surreptitiously.  There  is  considerable  evidence  that 
each  cuckoo  keeps  as  a  rule  to  one  kind  of  nest, 
and  although  over  a  hundred  different  kinds  of 
foster-parents  are  on  record,  the  list  of  favorites 
is  not  very  long.  It  includes  Hedge-Sparrow,  Pied 
Wagtail,  Titlark,  Tree  Pipit,  Robin,  Reed  Wren, 
Warblers,  Shrikes,  and  so  forth.  Unless  some  big 
mistake  is  made  the  foster-parents  incubate  the 
intruded  egg,  and  rear  the  young  cuckoo,  who 
sees  to  it  that  they  are  not  distracted  by  any  rival 
claimants.  The  parent  cuckoos  are  not  known  to 
take  any  interest  in  their  progeny,  and  they  leave 
our  shores  for  the  South  a  month  or  six  weeks  be- 
fore the  young  birds  are  able  to  travel.  The  "  para- 
sitism "  works  well,  and  in  the  Common  Cuckoo 
there  is  no  exception  to  it.  What  light  can  be  shed 
on  the  puzzle? 

There  are  three  considerations  that  make  the 
evasion  of  brooding  less  perplexing  than  it  appears 


42  SECRETS  OF  ANIMAL  LIFE 

at  first  sight.  ( i )  To  begin  with,  it  is  not  an  iso- 
lated phenomenon.  It  occurs  in  many  other  cuckoos 
and  in  the  quite  unrelated  Cow-Birds.  Some  kinds 
of  Old  World  Cuckoo  follow  the  usual  routine  of 
nesting  and  brooding;  the  American  Black-Billed 
Cuckoo,  though  usually  a  normal  nesting  and  brood- 
ing parent,  occasionally  puts  an  egg  in  the  nest  of 
another  bird;  at  least  one  species  of  Oriental 
Cuckoo  is  parasitic  in  one  part  of  the  country  and 
nests  in  another;  and  there  are  many  instances  of 
diverse  kinds  of  birds  casually  laying  in  the  nests 
of  their  neighbors.  Thus  the  cuckoo's  evasion  of 
the  normal  parental  duties  is  not  an  isolated 
phenomenon,  and  it  is  also  instructive  to  remember 
that  the  parasitic  instinct  is  not  always  perfect. 
Many  cases  are  known  of  a  cuckoo's  eg£  in  an 
altogether  unsuitable  nest,  for  instance,  in  that  of 
a  bird  which  does  not  feed  its  young  on  insects. 
(2)  A  second  consideration  is  that  the  mother- 
cuckoo's  behavior  is  congruent  with  some  other 
peculiarities  in  the  bird's  constitution  and  ways. 
Thus  there  are  far  more  males  than  females  (some- 
times perhaps  five  to  one),  and  polyandry  is  the 
natural  result,  as  has  happened  also  with  the  Cow- 
Birds.  And  while  it  is  probably  going  too  far 
to  call  the  polyandry  the  cause  of  the  parasitism, 
it  will  tend  to  a  slackening  of  parental  ties,  and  in 
any  case  the  parasitism  is  adapted  to  the  polyandry. 
Similarly,  the  great  fertility  of  the  cuckoo  (some- 
times credited  with  a  score  of  eggs,  though  a  dozen 
is  probably  nearer  the  truth)  is  as  likely  to  have 


CUCKOO  PUZZLES  43 

been  envolved  in  adaptation  to  the  risks  of  the  para- 
sitic habit  as  to  have  been  the  cause  of  it.  Very 
significant,  however,  is  the  interrupted  egg-laying, 
for  it  appears  that  the  mother  lays  five  to  seven 
on  alternate  days,  and  then  stops,  resuming  after  a 
short  interval  with  a  second  lot  of  four  or  five. 
This  would  not  fit  in  well  with  personal  incubation, 
but  it  is  congruent  with  the  parasitic  habit.  Again, 
since  the  adult  cuckoos  feed  very  largely  on  hairy 
caterpillars,  which  become  scarce  after  midsummer, 
there  is  an  economic  reason  for  the  early  migration 
and  for  leaving  the  care  of  the  young  to  others.  (3) 
Probably,  however,  we  get  most  light  on  the  prob- 
lem when  we  adopt  Professor  F.  H.  Herrick's  sug- 
gestion that  the  loss  of  the  nesting  instinct  is  due 
to  an  irregularity  in  the  rhythm  of  the  life-cycle 
— a  formula  which  covers  many  a  variation  among 
animals.  A  constitutional  change  of  deep  germinal 
origin  leads  to  the  suppression  of  one  chapter  and 
the  lengthening  out  of  another,  and  just  as  one 
kind  of  bird  may  take  to  building  supernumerary 
nests,  another  may  take  to  skipping  nest-building 
altogether.  A  lack  of  attunement  between  egg- 
laying  and  nest-making  is  casual  in  many  birds; 
it  has  become  established  in  cuckoos  because  it 
was  congruent  with  some  other  peculiarities  of 
constitution  and  habit,  and  because  it  was  found  to 
work  well.1 

Another  great  puzzle  concerns  the  cuckoo's  eggs. 

1  See  J.  Arthur  Thomson,  The  Wonder  of  Life  (Melrose, 
London,  1914),  p.  315. 


44  SECRETS  OF  ANIMAL  LIFE 

They  are  adapted  to  their  curious  history  in  being 
relatively  small  (though  with  considerable  variabil- 
ity in  size)  and  in  having  thick  resistant  shells,  but 
still  more  strikingly  in  being,  in  many  cases,  like 
facsimiles  of  the  eggs  of  the  selected  foster-parent. 
The  fine  "Fenton  Collection"  of  birds'  eggs  in  the 
University  of  Aberdeen  has  over  four  hundred 
cuckoo's  eggs  in  the  clutches  of  over  fifty  different 
kinds  of  foster-parents,  and  the  two  immediate 
impressions  that  one  gets  are,  first,  that  the  cuckoo's 
egg  is  often  a  perfect  copy  of  those  of  the  foster- 
parents;  and,  second,  that.it  is  often  obtrusively 
conspicuous.  Now  it  seems  to  be  practically  certain 
that  the  same  cuckoo  lays  the  same  type  of  egg  con- 
sistently, and  it  is  probable  that  Professor  Newton's 
theory  is  right,  that  having  a  blue  egg,  for  instance, 
may  be  hereditary  in  a  given  lineage,  and  that  there 
may  also  be  in  the  same  lineage  a  hereditary  pre- 
disposition to  put  the  egg  in  a  Redstart's  blue 
clutch.  If  the  cuckoo  is  hurried  or  flurried,  it  may 
put  the  egg  in  a  clutch  with  which  it  is  inharmoni- 
ous, and  as  this  often  succeeds  perfectly  well,  it 
seems  likely  that  some  kinds  of  birds  are  much  less 
sensitive  than  others  to  the  presence  of  an  intruded 
egg.  Thus  it  is  very  rarely  that  a  blue  Cuckoo's 
egg  is  found  in  the  blue  clutch  of  the  Hedge- 
Sparrow,  and  there  is  no  "mimicry"  between  a 
Cuckoo's  egg  and  a  Wren's. 

Another  of  the  major  cuckoo-puzzles  has  to  do 
with  the  behavior  of  the  young  bird  in  the  nest. 
What  Jenner  observed  so  carefully  in  1788,  several 


CUCKOO  PUZZLES  45 

naturalists  have  confirmed,  that  the  blind  and 
naked  young  cuckoo  manages  to  get  its  body  under- 
neath an  egg  or  a  nestling,  and  by  moving  con- 
vulsively backwards,  ousts  it  from  the  nest.  It  is  a 
prodigious  effort  for  a  puny  infant,  and  is  followed 
by  great  exhaustion.  After  a  rest,  however,  the 
eviction  may  be  repeated  if  necessary.  A  short 
time  ago  the  French  ornithologist  Raspail,  in  a 
paper  read  before  the  Zoological  Society  of  France, 
gave  expression  once  again  to  the  skepticism  which 
"Jenner's  legend"  has  often  aroused.  Pouncing 
upon  some  faked  photographs  of  the  alleged  evic- 
tion, Raspail  upbraided  naturalists  with  their 
credulity,  and  maintained  that  for  six  days  after 
hatching  it  is  a  physical  impossibility  for  the  young 
cuckoo  to  push  anything  whatever  outside  the  nest. 
What  happens,  according  to  Raspail,  is  that  the 
mother  cuckoo  keeps  an  eye  on  the  child  which  she 
has  put  out  to  nurse,  and  makes  room  for  it  in  the 
nest  by  picking  out  the  eggs  or  the  young  birds.  It 
is  admitted  that  a  cuckoo  in  depositing  its  egg  in 
a  nest  may  occasionally  puncture,  or  swallow,  or 
remove  one  or  more  of  the  others;  but,  circum- 
stantial as  Raspail's  picture  is,  we  adhere  to  what 
Newton  said  twenty  years  ago :  "  Of  the  assertion 
that  the  cuckoo  herself  takes  any  interest  in  the 
future  welfare  of  the  egg  she  has  foisted  on  her 
victim,  or  of  its  product,  there  is  no  evidence  worth 
a  moment's  attention."  It  may  sometimes  happen 
that  the  foster-parents  remove  a  broken  egg  or  a 
nestling  which  the  young  cuckoo  has  mechanically 


46  SECRETS  OF  ANIMAL  LIFE 

smothered,  but  there  is  no  doubt  as  to  the  general 
accuracy  of  Jenner's  description  and  Mrs.  Black- 
burn's drawing — the  young  cuckoo  clears  the  nest 
by  force.  It  is  a  mistake,  however,  to  call  it 
"criminal"  or  "murderer,"  for  it  does  not  know 
what  it  is  doing.  It  has  an  instinctive  capacity 
for  eviction,  and  that  has  in  all  likelihood  arisen  as 
an  elaboration  and  concatenation  of  certain  peculi- 
arities which  are  not  very  mysterious.  Just  as 
there  are  children  who  cannot  bear  to  be  touched, 
so  the  young  cuckoo  is  hyper-sensitive  to  pressure 
on  particular  parts  of  the  body,  such  as  the  sides. 
To  certain  pressures,  inevitable  in  a  nest  which  is 
too  small  for  it,  it  responds  by  throwing  itself 
backwards  or  by  convulsive  hitching  movements  of 
legs  and  arms.  The  flabby  infant  becomes  strong 
with  excitement,  and  performs  feats  of  strength 
which  seem  scarcely  credible.  In  any  case  it  gets 
the  nest  to  itself,  and  its  foster-parents  seem  to  be 
quite  proud  of  their  unusually  large  baby,  whose 
appetite  keeps  them  very  busy. 


VII 
THE  FROG'S  YEAR 

SPEAKING  of  our  British  frog,  Ram  tempo- 
raria,  Dr.  Gadow  writes :  "  Next  to  Man  there 
is  no  animal  which  has  been  studied  so  minutely, 
and  has  had  so  many  primers  and  text-books  written 
on  it,  as  this  frog.  In  spite  of  all  this  it  is  very 
little  understood."  Perhaps  there  may  be  some 
interest,  therefore,  in  following  its  familiar  life- 
cycle  round  the  year.  In  Scotland  it  is  usually  in 
March  that  the  frogs  leave  their  winter-quarters 
and  betake  themselves  from  near  or  far  to  standing 
or  slowly  flowing  water.  The  winter-quarters  are 
described  by  Gadow  in  the  Cambridge  Natural 
History  as  "mostly  holes  in  the  ground,  under 
moss,  or  in  the  mud,"  and  Mr.  O.  H.  Latter,  ia  his 
Natural  History  of  some  Common  Animals,  speaks 
of  our  frogs  as  hibernating  "  some  in  holes  and 
drain-pipes,  others  in  or  on  the  mud  at  the  bottom 
of  ponds."  In  his  Ray  Society  monograph  Dr. 
Boulenger  says  that  "  many  males  hibernate  under 
water."  It  seems,  then,  that  the  grass-frog's  habits 
vary  considerably  in  different  parts  of  its  very  wide 
range,  and  that  some  of  them  pass  the  winter  in 
sheltered  recesses  far  from  the  water.  It  should  be 
noted  that  the  grass- frog's  near  relative,  the  common 

47 


48  SECRETS  OF  ANIMAL  LIFE 

edible  frog  or  water-frog,  Rana  esculenia,  habitually 
spends  its  winter  in  the  mud  of  the  pond,  while 
in  some  other  species  the  females  hide  during 
winter  under  moss,  among  leaves,  and  the  like, 
while  the  males  take  to  the  moist  mud.  The 
internal  economy  of  the  winter  torpor  (perhaps  the 
word  hibernation  is  best  kept  for  mammalian 
winter-sleepers)  is  of  great  interest.  The  fire  of 
life  burns  low;  no  food  is  taken;  a  minimum  of 
energy  is  expended;  the  reserves  stored  in  the  liver 
and  in  the  "  fatty  bodies "  are  slowly  used  up ; 
the  respiration  sinks  back  to  a  primitive  mode — by 
means  of  the  blood-vessels  spread  out  in  the  skin. 
None  the  worse  for  their  long  fast,  the  frogs 
bestir  themselves  as  the  winter  disappears,  and 
pair  in  the  pools,  often  in  very  unsuitable  places 
where  the  spawn  is  soon  left  stranded.  The  males 
call  to  their  mates,  and  their  croaking  capacities 
(due  to  vocal  cords  in  the  larynx)  are  enhanced  by 
the  presence  of  two  internal  resonating  sacs  which 
lie  at  the  posterior  corners  of  the  mouth  and  bulge 
outwards  when  inflated.  These  sacs  are  not  de- 
veloped in  the  females,  who  give  voice  much 
more  rarely,  and  certainly  do  not  respond  vocally 
to  the  males'  serenading.  In  the  calls  of  different 
species  of  frog  there  is  a  striking  individuality,  and 
we  cannot  hear  even  the  dull  "grook,  grook"  of 
the  grass-frog  in  the  early  spring '  without  a  thrill 
deeper  than  the  cuckoo's  wandering  voice  gives  us 
later  on.  For,  apart  from  the  instrumental  music  of 
insects,  the  first  voice  in  the  evolution  of  animals  to 


THE  FROG'S  YEAR  49 

break  the  silence  of  Nature  was  that  of  Amphibians. 
The  primary  function  of  the  voice  was  probably  as  a 
sex  call,  and  that  is  its  almost  exclusive  use  in  frogs. 
After  the  breeding  season  is  over,  the  male  grass- 
frog  is  almost  as  taciturn  as  the  female.  It  is 
surely  suggestive  to  think  of  the  secondary  employ- 
ment of  the  voice  in  higher  vertebrates  in  protecting 
and  fostering  the  young,  in  expressing  pain  and 
pleasure,  in  communicating  social  news.  As  Pro- 
fessor Holmes  notes  in  his  interesting  Studies  in 
Animal  Behaviour  (1916)  :  "The  evolution  of  the 
voice  in  vertebrates  doubtless  influenced  in  a  marked 
degree  the  evolution  of  the  sense  of  hearing.  It  is 
not  improbable,  therefore,  that  the  evolution  of 
the  voice,  with  all  its  tremendous  consequences  in 
regard  to  the  evolution  of  mind,  is  an  outgrowth  of 
the  differentiation  of  sex." 

In  this  connection  it  is  worth  noticing  that 
although  frogs  have  poor  brains,  and  are  of  course 
limited  by  their  "cold-bloodedness,"  which  makes 
their  changeful  body-temperature  approximate  to 
that  of  their  immediate  surroundings,  they  are  pro* 
foundly  affected  at  the  sex  season.  The  pairing 
and  egg-laying  may  occur  while  there  are  still 
lumps  of  ice  in  the  water,  and  before  the  creatures 
have  broken  their  fast!  The  male  has  not  only 
his  resonating  sacs,  but  a  curiously  swollen  and 
hardened  tetrapartite  pad  on  his  first  finger,  which 
he  uses  in  violently  embracing  his  mate.  His 
whole  skin  changes  considerably,  and  often  shows 
a  beautiful  bluish  sheen.  The  character  of  the 


50  SECRETS  OF  ANIMAL  LIFE 

female's  skin  also  changes,  and  she  puts  on  here 
and  there  an  adornment  of  pinhead-like  pearls  of  a 
white  or  pale-reddish  color.  In  some  cases  the 
pairing  is  fatal  to  the  females;  in  some  cases  the 
grass-frogs  burrow  into  the  mud  after  the  spawning 
is  over,  and  rest  for  about  a  fortnight  before  they 
leave  for  the  summer-quarters. 

The  globes  of  jelly  surrounding  the  frog's  ova 
(one  female  may  lay  two  thousand)  correspond  to 
the  white  of  egg  in  a  hen's  egg,  and  serve  many 
useful  purposes.  To  begin  with,  the  masses  of 
spawn  sink  or  tend  to  sink  to  the  floor  of  the  pool; 
but  the  spheres  of  jelly  swell  rapidly,  some  bubbles 
of  gas  (probably  oxygen  from  adjacent  submerged 
plants)  help  to  buoy  them  up,  and  the  clumps  rise 
to  the  surface.  The  spheres  of  jelly  form  elastic 
cushions  round  the  developing  eggs;  their  un- 
palatability  and  slipperiness  save  the  embryos  from 
their  enemies;  they  lessen  the  risks  of  drought; 
perhaps  each  crystal  globe  acts  like  a  little  glass 
house.  In  the  interstices  between  the  spheres  there 
are  often  minute  green  Algae  which  give  off  oxygen 
in  the  sunlight  and  thus  have  a  useful  aerating 
function.  There  is  also  a  micro-fauna  of  frog's 
spawn,  and  some  of  the  associated  little  creatures 
are  of  service  in  loosening  the  jelly  when  the  larvae 
are  ready  to  escape.  The  dark  pigment  in  the  upper 
hemisphere  of  the  egg  seems  of  use  in  absorbing 
heat-rays,  and  in  ordinary  cases  the  larvae  begin 
to  move  about  in  the  jelly  some  three  weeks  after 


THE  FROG'S  YEAR  51 

their  life  began — that   is,   after  the  eggs   at  the 
moment  of  being  laid  were  likewise  fertilized. 

Peculiar  half-finished  little  creatures  the  newly- 
hatched  larvae  are — mouthless,  limbless,  blind, 
covered  with  microscopic  cilia,  with  just  the  be- 
ginnings of  a  first  set  of  gills.  They  attach  them- 
selves by  a  horseshoe-shaped  cement-organ  to  water 
weed,  and  subsist  for  some  time  on  a  legacy  of 
yolk.  It  is  an  often-told  story  how  these  newly- 
hatched  larvae  develop  into  true  tadpoles,  with  open 
mouth,  gill-clefts,  and  a  second  set  of  gills;  how 
the  limbs  bud  out;  how  the  lungs  develop  and  the 
two-month-old  pollywogs  learn  to  use  them,  taking 
gulps  of  air  at  the  surface;  how  the  circulation 
changes  from  a  piscine  to  an  amphibian  type;  and 
,how  after  nearly  three  months  have  passed  there 
is  a  striking  metamorphosis,  the  outcome  of  which 
is  a  tiny  frog.  The  substance  of  the  tail  is  broken 
up,  and  dissolved  as  if  a  pathological  process  had 
become  normalized;  the  amoeboid  phagocytes  which 
play  such  an  important  role  in  inflammation  have 
their  share  in  changing  the  tadpole  into  a  frog, 
now  acting  as  sappers  and  miners,  and  again  as 
transporting  agents.  The  mouth  changes  its  char- 
acter entirely;  the  tongue,  hitherto  small,  increases 
notably;  the  eyes,  hitherto  beneath  the  skin,  reach 
the  surface  at  last.  It  is  time  for  the  young  frog  to 
get  ashore,  else  it  will  drown.  It  has  been  shown 
experimentally  that  not  even  the  common  water- 
frog  can  live  under  water  for  more  than  ten  minutes, 


52  SECRETS  OF  ANIMAL  LIFE 

except,  of  course,  when  in  the  torpid  state  into  which 
they  sink  in  winter,  when  the  reduction  of  vitality 
minimizes  the  demand  for  oxygen. 

There  is  much  in  the  familiar  sequence  of  events 
that  is  extraordinarily  interesting,  such  as  the  re- 
capitulation of  racial  evolution  on  the  one  hand 
and  the  specificity  on  the  other.  Thus  there  is  no 
doubt  that  the  young  tadpole  has  a  two-chambered 
heart  like  that  of  most  fishes  and  a  piscine  type 
of  circulation.  This  reads  like  recapitulation.  Yet 
the  tadpole's  two  sets  of  gills  are  quite  different 
from  those  of  ordinary  fishes,  and  its  skin  is  an 
amphibian's  skin  from  first  to  last.  This  is  specifi- 
city. There  is  a  pretty  point  in  regard  to  the 
tongue,  which  is  at  first  non-mobile,  just  as  is  the 
case  in  fishes.  Gradually  muscle-fibers  increase  in 
the  tadpole's  tongue,  and  the  foundations  are  laid 
of  the  highly  developed  musculature  that  enables 
the  frog  to  shoot  out  its  tongue  in  a  somersault 
on  the  unwary  fly.  Another  general  fact  of  in- 
structive value  is  the  succession  of  varied  solutions 
of  the  same  fundamental  problems.  The  sequence 
of  diverse  modes  of  respiration  is  remarkable.  The 
newly-hatched  larva  breathes  cutaneously;  then 
three  pairs  of  so-called  external  gills  develop;  then 
the  mouth  is  indimpled  and  gill-clefts  open  out 
from  the  pharynx  to  the  exterior;  then  a  gill- 
chamber  is  formed  and  a  second  set  of  gills  replaces 
the  first;  then  gills  and  lungs  are  used  at  the  same 
time,  just  as  in  Dipnoan  mud-fishes;  finally  the  small 
fully-formed  frog  is  a  lung-breather,  with  its  skin 


THE  FROG'S  YEAR  53 

to  fall  back  on  if  necessary.  The  changes  in  diet 
are  equally  striking. 

But  while  the  elusive  tadpoles  have  been  under- 
going development  in  the  relatively  safe  conditions 
of  aquatic  life,  their  parents  have  been  living 
dangerously  on  land.  In  April  or  earlier  the  old 
frogs  pass  from  the  pond  or  pool  to  the  meadows, 
woods,  and  fields,  where  they  hunt  for  insects, 
slugs,  worms,  and  other  small  fry,  which  must  be 
moving  to  excite  interest.  The  adults  are  followed 
in  June  or  July  by  the  froglings  of  the  year,  which 
often  migrate  from  the  water-pools  in  huge  numbers. 
Their  sudden  appearance  has  formed  part  of  the 
basis  of  stories  of  frog-showers,  and  we  need  not 
smile  too  broadly  who  still  speak  of  it  "raining 
cats  and  dogs."  The  crowd  of  small  frogs,  each 
well  under  half  an  inch  in  length — much  shorter 
than  the  tadpole — is  occasionally  so  thick  that  when 
we  meet  them  crossing  a  road  we  find  it  difficult 
to  pass  without  treading  on  them. 

In  the  fields  they  indulge  their  insectivorous 
appetite  and  grow — but  not  very  quickly.  Every 
now  and  then  they  molt — that  is  to  say,  the  outer- 
most layer  of  the  epidermis,  often  much  the  worse 
for  wear,  is  split  up  along  the  mid-line  of  the  back 
and  slipped  off.  It  seems  to  be  good  form  that 
the  frog  should  tuck  its  cast  slough  into  its  mouth, 
setting  a  fine  example  of  economy.  In  spite  of 
their  adjustable  protective  coloration,  which  often 
gives  them  a  garment  of  invisibility  against  a  back- 
ground of  either  brown  earth  or  green  grass,  our 


54  SECRETS  OF  ANIMAL  LIFE 

frogs  fall  victim  to  the  appetite  of  many  enemies, 
such  as  birds  of  prey,  stoats,  and  grass-snakes, 
so  that  only  a  fraction  of  the  young  migrants  is 
left  to  make  the  return  journey  in  late  autumn. 
They  are  then  about  three-quarters  of  an  inch  long. 
As  the  grass-frog  does  not  become  mature  for  three 
years,  it  is  likely  that  some  of  the  youngsters 
winter  in  suitable  quarters  far  afield.  But  Dr. 
Hempelmann,  the  author  of  a  fine  recent  (1908) 
monograph  on  the  frog,  says  of  the  species  we  have 
been  discussing  that  the  adults  usually  seek  out 
the  water  again  in  autumn  and  spend  about  four 
months  of  winter  buried  in  the  mud  thereof.  What- 
ever be  the  exact  truth  about  the  winter-quarters, 
the  frog's  year  is  eventful  indeed.  How  many 
years  are  granted  it  we  do  not  know. 


VIII 
THE  EDUCABILITY  OF  A  SNAIL 

IT  has  been  well  established  that  a  common 
garden-snail  can  find  its  way  home  over  difficult 
country  from  a  distance  of  six  yards  or  more. 
Of  one  that  habitually  spent  the  day  in  a  hole  in 
a  garden  wall,  about  four  feet  from  the  ground, 
it  is  recorded  that  for  months  it  utilized  as  a  noc- 
turnal ladder  a  piece  of  wood  sloping  from  a  bed 
of  herbs  to  near  the  hole.  Darwin  mentions  in 
The  Descent  of  Man  the  case  of  two  Roman  snails, 
one  sickly  and  the  other  vigorous,  which  were 
placed  in  an  ill-provided  garden.  The  vigorous  one 
went  over  the  wall  into  the  next  garden,  where 
food  was  abundant.  It  was  absent  for  twenty-four 
hours,  but  when  suspicion  was  growing  strong  that 
it  had  deserted  its  companion,  it  returned,  and  after 
a  short  time  both  disappeared  over  the  wall.  That 
the  explorer  was  able  to  tell  the  invalid  of  the 
El  Dorado  over  the  steep  mountains  is  very  im- 
probable, but  the  return  to  the  starting-point  is 
quite  in  line  with  other  observations.  It  is  likely 
enough  that  the  scent  of  the  slimy  trail  may  assist 
in  the  way-finding,  though  it  does  not  seem  certain 
where  the  sense  of  smell  has  its  seat  in  the  common 
snail.  But  apart  from  evidence  of  " homing" 

55 


56  SECRETS  OF  ANIMAL  LIFE 

and  a  few  instances  of  profiting  by  experience 
(e.g.  the  effective  behavior  of  water-snails  dropped 
into  an  aquarium  in  which  they  had  previously 
lived),  there  has  hitherto  been  little  basis  for  an 
answer  to  the  question:  "Can  a  snail  learn?" 
But  a  satisfactory  answer  has  now  rewarded  a  series 
of  exceedingly  careful  experiments  made  by  Miss 
Elizabeth  Lockwood  Thompson  (Behaviour  Mono- 
graphs, vol.  iii,  No.  3,  1917,  Cambridge,  Mass.), 
and  it  is  encouraging  to  learn  that  the  answer  is  in 
the  affirmative.  Even  a  worm  will  turn;  even  a 
snail  will  learn.  Who  shall  set  limits  to  education? 
Miss  Thompson  studied  the  learning  process  in  a 
common  water-snail,  Physa  gyrina  by  name,  which 
is  wont  to  glide  about  in  ponds,  mouth  and  creeping 
sole  upwards,  suspended  to  the  surface  film.  The 
method  of  the  research  was  a  distinctly  ingenious 
modification  of  a  well-known  experiment  associated 
with  the  name  of  the  famous  Russian  physiologist, 
Ivan  Petrovich  Pavlov.  A  dog's  mouth  waters  at 
the  sight  or  smell  of  food,  and  it  is  possible  to 
measure  the  quantity  and  quality  of  the  secretion. 
With  the  primary  stimulus  of  food  Pavlov  associ- 
ated some  sound  or  color,  and  after  a  time  the  dog 
mastered  or  registered  the  association  so  thoroughly 
that  the  sound  or  color  served  of  itself  to  evoke 
the  mouth-watering".  The  shadow,  so  to  speak, 
worked  like  the  substance — somewhat  in  the  same 
way  as  the  sight  of  a  menu-card  may,  within  limits, 
serve  as  an  appetizer.  Miss  Thompson  observed 
that  when  the  immediate  neighborhood  of  the 


THE  EDUCABILITY  OF  A  SNAIL       57 

snail's  mouth  was  touched  with  a  little  piece  of 
food,  such  as  lettuce,  there  followed  a  number — 
about  four  was  common — of  rapid  mouth-move- 
ments, opening  and  closing,  in  fact.  These  obviously 
correspond,  in  the  logic  of  the  experiment,  to  the 
mouth-watering  of  Pavlov's  dog. 

The  next  step  was  to  find  a  practicable  secondary 
stimulus,  and  that  used  was  pressure  on  the  snail's 
foot  or  creeping  sole  with  a  clean  glass  rod.  This 
does  not  normally  evoke  any  mouth-movement, 
except  in  rare  cases,  which  are  readily  explained. 
The  next  step  was  to  apply  simultaneously  the  two 
stimulations,  the  touch  of  food  near  the  mouth 
and  the  pressure  of  the  glass  rod  on  the  foot.  To 
this  for  a  time  no  answer  at  all  was  given.  It  was 
not  till  the  snails  had  been  tried  sixty  to  one  hundred 
and  ten  times  that  they  began  to  answer,  but  after 
the  Rubicon  was  crossed  they  answered  back  all 
the  rest  of  the  total  of  two  hundred  and  fifty  trials. 
It  was  noteworthy,  however,  that  the  number  of 
mouth-movements  in  a  single  response  did  not 
reach  so  high  an  average  as  was  exhibited  when  the 
food  stimulus  was  used  by  itself.  The  snails  that 
gave  the  normal  answer-back  to  the  two  stimuli 
applied  simultaneously  were  regarded  as  "  trained," 
and  were  ready  for  the  next  and  crucial  step  in  the 
experiment.  Forty-eight  hours  after  the  comple- 
tion of  their  training  the  snails  were  tried  with  the 
foot-pressure  stimulus  by  itself.  The  dux  of  the 
class  gave  the  proper  mouth-moving  answer  the 
first  seven  trials  right  away;  two  other  answers 


58  SECRETS  OF  ANIMAL  LIFE 

were  given  ninety-six  hours  after  the  end  of  the 
training.  Other  members  of  the  class  behaved  in 
a  similar  way,  but  beyond  the  limit  of  ninety-six 
hours  no  answer  could  be  wrung  out  of  any  of  them. 
There  was  a  sudden  and  final  declinature  to  answer, 
which  further  experimentation  showed  to  have  no 
necessary  connection  with  fatigue. 

In  some  of  the  many  sets  of  experiments,  the 
punctilious  carefulness  of  which  deserves  high 
praise,  there  was  an  interesting  waning  in  the 
number  of  mouth-movements  in  any  one  answer. 
Following  a  maximum  number  of  mouth-move- 
ments in  a  response  towards  the  middle  of  the  series 
of  trials,  the  number  gradually  diminished  to  the 
end  of  the  series.  This  indicated  that  the  snails 
were  becoming  adapted  to  a  stimulus  which  was 
not  being  followed  by  any  reward.  But  the  general 
result  stands  out  clearly,  and  considering  the  humble 
creatures  involved,  is  of  very  considerable  interest. 
Snails  which  gave  no  mouth  response  to  pressure 
on  the  foot  were  so  affected  by  the  simultaneous 
application  of  pressure  to  the  foot  and  food  to  the 
mouth  that  they  then  gave  the  mouth  answer  to 
pressure  on  the  foot.  The  effect  of  training  with 
the  simultaneous  stimuli  persisted  for  ninety-six 
hours  after  the  training  stopped.  The  snail  learned 
its  lesson,  but  the  registration  of  experience,  memory 
in  psychological  language,  was  shortlived. 

Those  who  have  some  acquaintance  with  fresh- 
water snails  may  be  inclined  to  think  that  Miss 
Thompson's  pupils  were  extraordinarily  well  be- 


THE  EDUCABILITY  OF  A  SNAIL       59 

haved.  For  what  captured  specimens  very  gener- 
ally do  on  the  slightest  provocation — even  jarring 
the  aquarium  a  little — is  to  expel  the  air  from  their 
breathing  chamber,  retract  into  their  shell,  and  drop 
to  the  bottom,  where  they  may  sulk  for  an  hour. 
Realizing  that  this  nervousness  would  make  ex- 
perimenting impossible,  Miss  Thompson  began  by 
"taming"  her  captives.  They  were  taken  in  the 
hand  at  intervals  and  moved  about  under  water; 
they  were  held  till  they  protruded  from  the  shell; 
they  were  abundantly  handled,  till  they  became  so 
accustomed  to  it  that  they  could  be  touched  by  the 
observer,  or  moved  from  one  dish  to  another,  with- 
out retracting  their  body  or  expelling  the  air  from 
their  lung.  This  "  taming"  is  a  further  evidence  of 
adaptability. 

Very  interesting  data  as  to  the  educability  of 
animals  have  been  obtained  by  using  simple  laby- 
rinths in  which  the  creatures  are  placed  at  repeated 
intervals  to  see  whether  they  learn  to  get  out  more 
quickly  in  the  course  of  experience.  It  has  been 
found  useful  in  many  cases  to  reward,  say  with 
food,  a  rapidly  successful  solution  of  the  labyrinth, 
and  to  punish,  say  with  a  slight  electric  shock,  the 
taking  of  the  wrong  road.  Most  of  these  experi- 
ments have  been  made  with  animals  of  high  degree 
like  cats  and  mice ;  Miss  Thompson  has  spent  much 
time  and  ingenuity  in  inquiring  whether  the  laby- 
rinth experiment  can  be  adjusted  so  as  to  apply  to 
freshwater  snails.  In  one  form  of  the  experiment 
a  Y-shaped  cylindrical  glass  tube  was  anchored 


60  SECRETS  OF  ANIMAL  LIFE 

to  the  floor  of  the  aquarium.  One  arm  was  made 
rough  internally,  and  at  its  upper  end  the  snail 
received  an  electric  shock,  of  which  the  roughness 
was  meant  to  be  the  "warning."  The  smooth  arm 
of  the  tube  led  to  the  surface  of  the  water,  where 
fresh  air  is  obtained — sufficient  reward  in  itself. 
The  experiment  consisted  in  pressing  the  air  from 
the  snail's  lung  and  then  placing  it  at  the  base  of 
the  so-called  labyrinth.  It  is  of  value  to  the  snail 
to  get  its  lung  filled  as  soon  as  possible;  this  is 
attained  by  creeping  up  the  smooth  arm,  it  is  missed 
by  creeping  up  the  rough  one;  and  the  failure  is 
emphasized  by  a  mild  punishment,  the  slight  electric 
shock.  But  the  result  of  the  pretty  experiment  was 
to  show  a  complete  incapacity  to  profit  by  experi- 
ence to  the  extent  of  solving  the  problem.  The 
percentage  of  error  did  not  diminish  as  the  series 
of  trials  lengthened;  indeed,  things  sometimes  got 
worse  instead  of  better. 

In  one  interesting  set  of  experiments  a  power  of 
forming  associations  was  displayed,  but  it  was 
not,  so  to  speak,  followed  up.  Both  arms  were 
smooth,  but  the  wrong  road  had  as  its  warning 
notice-board  an  irritating  hair  which  was  made  to 
touch  the  snail's  horns  and  the  back  of  its  head. 
Immediately  on  the  heels  of  the  warning,  if  the 
snail  persisted  on  its  wrong  course,  came  the  punish- 
ment of  a  shock.  Now,  in  15.6  per  cent,  out  of  a 
total  of  nine  hundred  and  thirty  trials,  the  snails 
changed  their  course  from  the  wrong  to  the  right 
path  after  contact  with  the  warning  stimulus,  but 


THE  EDUCABILITY  OF  A  SNAIL       61 

before  the  shock  or  punishment  was  received.  This 
looked  like  profiting  by  experience,  but  the  snails 
showed  no  ability  to  utilize  this  in  the  further 
step  of  solving  the  labyrinth.  Selective  ability  is 
apparently  lacking.  The  interest  of  Miss  Thomp- 
son's admirably  conducted  investigation  is  partly  in 
its  ingenious  methods,  and  partly  in  its  demonstra- 
tion of  the  educability  of  a  very  unpromising  sub- 
ject. Here  we  are  on  the  threshold  of  a  quality  that 
especially  marks  brains  not  loaded  with  ready-made 
capacities  of  instinctive  behavior,  the  quality 
which  Sir  Ray  Lankester  has  called  educability,  the 
quality  of  being  able  to  learn. 


IX 
THE  CULT  OF  SHELLS 

TO  children  and  to  those  who  remain  young 
in  eye,  to  artists  and  to  unsophisticated  per- 
sons generally,  shells  always  make  a  strong  appeal 
— and  who  can  wonder  ?  For  shells  have  lines  that 
flow,  and  shapes  that  sing,  and  colors  that  make 
melody.  Each  is  the  constructive  work  of  the  life- 
time of  a  very  intricate,  yet  harmoniously  unified, 
creature;  each  is  an  architectural  achievement 
that  has  stood  the  test  of  time  for  ages.  Every 
mollusk  expresses  itself  in  its  house  (in  a  way  man 
rarely  does  in  his) ;  and  it  has  often  an  interesting 
personal  way  of  registering  in  its  shell  some  of  the 
crises  of  its  life,  just  as  a  tree  records  in  its  rings 
a  summer  of  great  drought  or  an  autumn  of  very 
early  frost.  There  is  a  sheer  sensory  delight  in 
looking  at  a  box  of  different  kinds  of  cowries, 
cones,  or  olivas;  there  is  a  higher  perceptual  ad- 
miration in  studying  the  well-adapted  edifices  built 
by  architects  whose  designs  are  dreams  rather 
than  thoughts;  there  is  an  even  subtler  glow  in 
sharing  vicariously  in  that  triumph  of  life  over 
materials  which  many  shells,  like  the  Nautiloids, 
so  well  illustrate;  but,  besides  these  factors,  may 
there  not  be  in  our  delight  over  shells  some  echo 

62 


THE  CULT  OF  SHELLS  63 

of  the  impact  which  they  made  long  ago  on  the 
mental  framework  of  our  ancestors?  The  child 
holds  the  shell  to  its  ear,  and  listens  to  the  supposed 
reverberation  of  the  sea.  What  it  hears  is  the 
sympathetic  resonance  of  vibrations  selected  by  the 
shell  from  the  outside  aerial  turmoil,  though  some 
say  a  little  is  due  to  the  internal  vibrations  of 
pulsing  blood-vessel  and  tensely-strung  muscle. 
But  we  wonder  whether  there  may  not  be  in  the 
familiar  childish  experience  some  echoing  recapitu- 
lation of  a  very  old,  very  widespread,  racial  custom. 
For  the  cult  of  shells  goes  back  to  remote  antiquity, 
and  for  millennia  simple  peoples  listened  to  the  voice 
of  God  in  the  sea-snail's  shell. 

Of  the  great  interest  of  shells  to  students  of 
human  history  we  have  had  a  recent  revelation  in 
Mr.  Wilfrid  Jackson's  learned  work  on  Shells  as 
Evidence  of  the  Migrations  of  Early  Culture 
(1917),  one  of  the  ethnological  publications  of  the 
University  of  Manchester.  To  this  memoir  Pro- 
fessor Elliot  Smith  contributes  a  luminous  introduc- 
tory essay,  which  helps  us  to  understand  the  grip 
which  shells  took  of  human  nature  in  the  days  of  its 
impressionable  youth.  A  new  light  is  also  thrown, 
as  he  says,  on  the  curiously  logical  sequence  of 
Father  O'Flynn's  intellectual  achievements — 

Down  from  mythology  into  thayology, 
Troth!  and  conchology,  if  he'd  the  call. 

In  many  cases,  as  it  seems  to  us,  where  living 
creatures  or  their  products  have  strongly  gripped 
mankind,  there  have  been  three  factors  at  work — 


64  SECRETS  OF  ANIMAL  LIFE 

practical,  aesthetic,  and  imaginative.  This  is  surely 
true  of  shells.  Throughout  the  greater  part  of  the 
world  simple  peoples  have  used  various  shellfish 
(an  abhorrent  word  to  the  zoologist)  for  food;  and 
this,  of  course,  continues,  whether  in  oysters,  which 
Huxley  likened  to  "gustatory  flashes  of  summer 
lightning,"  or,  at  the  other  pole  of  expenditure,  in 
winkles,  which  require  no  apology.  And  apart  from 
edibility  and  the  use  of  mollusks  as  bait,  many  shells 
have  proved  of  practical  service  to  man  as  instru- 
ments or  parts  of  instruments.  Secondly,  the 
decorative  or  emotion-exciting  value  of  shells  has 
been  appreciated  all  over  the  world,  the  waist- 
band of  cowries  and  the  necklace  of  pearls  having 
the  same  merit  of  great  beauty,  enhanced  in  both 
cases,  no  doubt,  by  monetary  and  other  associations. 
And,  thirdly,  it  seems  quite  certain  that  infectious 
imaginative  suggestions,  perhaps  rather  fanciful 
and  arbitrary  to  start  with,  have  given  certain  shells 
psychological  value  as  symbols,  charms,  and 
amulets.  We  venture  to  think  that  some  anthro- 
pologists who  have  emphasized  the  symbolism  of 
certain  shells,  notably  cowries,  have  tended  to 
underestimate  the  associated  practical  and  sensory 
values.  We  fancy  that  the  wide  diffusion  of  a 
recognition  of  the  symbolic  significance  of  certain 
shells  was  partly  due  to  their  correlated  beauty  and 
usefulness.  In  any  case,  the  three  factors  must  have 
co-operated,  as  some  examples  will  show. 

One  of  the  many  undated  human  inventions  was 
that    of  the    shell-trumpet.      It    may    have    been 


THE  CULT  OF  SHELLS  65 

suggested  by  listening  to  the  shell-murmur.  For 
here  is  a  conch  with  a  hole  at  the  top  or  towards  the 
top;  it  will  not  sing  as  the  others  do;  let  some 
breath  be  blown  into  it — for  breath  spells  life — 
and  the  strong-lunged  youth  had  his  surprise!  In 
response  to  his  pulmonary  blast  there  came  forth  a 
trumpet-call — resonant,  vibratory,  wailing,  terrific 
— like  the  voice  of  the  wind-god.  It  is  even  now 
an  instructive  experience  to  get  a  strong-lunged 
expert  to  blow  a  first-class  shell-trumpet  in  the 
quiet  of  an  academic  museum  after  hours.  A  force- 
ful, insurgent,  fog-horn  call,  with  a  volume  that 
makes  one  a  little  ashamed,  with  cadences  that 
startle — and  how  all  the  " curiosities"  from  Ceylon 
and  Malay,  from  California  and  Madagascar,  seem 
to  reverberate!  For  it  is  an  old,  old  story.  The 
important  fact  was  the  vast  effectiveness  of  the 
shell-trumpet's  voice,  likewise  the  disproportion 
between  effect  and  cause.  So  the  Triton,  or  some 
other  conch,  was  blown  to  summon  men  to  the 
temple  and  to  the  battle ;  it  was  used  for  emotional 
effects  (and  for  symbolic  reasons)  at  marriages  and 
initiations;  and  it  was  not  perplexing  to  our  fore- 
fathers that  what  was  official  and  symbolic  one  day 
should  be  a  fog-horn  or  a  cattle-call  the  next.  What 
served  to  scare  off  evil  spirits  would  also  serve 
to  frighten  thieves.  The  shell-trumpet  was  effective 
and  it  was  also  beautiful. 

The  Minoans  of  Crete  were  the  first  to  manu- 
facture the  famous  purple  dye  from  sea-snails  like 
Murex  and  Purpura;  the  Phoenicians  followed  and 


66  SECRETS  OF  ANIMAL  LIFE 

dipped  their  precious  fabrics  in  the  vats  of  Tyre 
and  Sidon;  the  news  of  the  glorious  color  spread; 
and  masses  of  broken  shells  still  betray  to  the 
archaeologist  the  diffusion  of  the  purple  industry 
round  the  shores  of  the  Mediterranean  and  the 
Red  Sea  and  far  beyond  both.  There  was  ancient 
purple-dyeing  in  Great  Britain  and  Ireland,  in 
Central  America  and  Mexico,  in  Malay,  China,  and 
Japan.  The  process  of  extracting  the  dye  was  so 
peculiar  and  distinctive  that  probabilities  are 
strongly  in  favor  of  the  view,  which  Mr.  Wilfrid 
Jackson  supports,  that  the  secret  was  carried  from 
the  Old  World  to  the  New  by  early  Mediterranean 
seafarers.  The  snail's  secretion  went  through 
curious  changes — colorless,  yellow,  green,  bluish — 
before  it  flushed  into  the  fine  purple-red;  and 
that  added  to  beauty  a  suggestion  of  mystery. 
The  final  color  hinted  at  blood,  and  this  again  at 
vitality.  Multitudes  of  snails  were  required  in  order 
to  yield  a  little  dye,  and  this  meant  many  adven- 
turous cruises,  and  these  often  meant  many  lives. 
So  costliness  embellished  beauty,  and  the  glamour  of 
purple  grew.  Only  a  few  men  dare  don  purple  robes, 
only  a  few  women  dare  use  the  purple  cosmetic,  only 
the  admiral's  ship  or  Cleopatra's  could  have  purple 
sails,  only  sacred  script  could  enjoy  the  purple  glory. 
Another  aesthetic  appeal  came  from  pearls  and 
mother-of-pearl,  the  beauty  of  which  has  never 
ceased  to  charm.  To  the  aesthetic  glamour  of 
pearls  was  added  the  romantic  touch  of  their 
mysterious  origin,  and  it  is  interesting  to  find 


THE  CULT  OF  SHELLS  67 

that  a  theory  connecting  them  with  dewdrops  is 
geographically  very  widespread.  From  head- 
quarters on  the  shores  of  the  Red  Sea,  where 
fisheries  were  established  long  before  the  time 
of  the  Ptolemies,  the  appreciation  of  pearls  spread 
far  and  wide,  in  the  New  World  as  well  as  in  the 
Old.  It  is  well  known  that  pearls  took  pre- 
cedence over  all  other  gems  among  the  Romans 
and  "  according  to  Suetonius,  the  great  motive  of 
Caesar's  expedition  into  Britain  in  55  B.C.  was  to 
obtain  its  pearls,  which  were  so  large  that  he  used 
to  try  the  weight  of  them  by  his  hand."  These 
were,  of  course,  the  productions  of  freshwater 
mussels.  The  modern  zoologist  knows  that  pearls 
are  produced  by  the  reaction  of  the  mollusk's  skin 
to  some  minute  focus  of  irritation,  which  may  be 
the  microscopic  larva  of  a  tapeworm  or  fluke,  or 
a  blob  of  conchin  (the  organic  foundation  of  the 
shell),  or  even  an  inorganic  particle.  This  was,  of 
course,  unknown  to  the  ancients,  but  it  is  interest- 
ing to  find  from  remote  antiquity  the  outcrop  of 
various  recipes  for  the  artificial  stimulation  of 
pearl-production  within  the  mollusk.  With  a 
different  smack  are  the  old  tales  that  if  pearls  are 
sealed  up  for  a  time  in  a  box  along  with  a  little  rice 
they  wijl  be  found  to  have  multiplied.  The 
originals  will  not  be  any  the  worse;  only  the  ends 
of  the  rice-grains  will  show  an  appearance  of  having 
been  nibbled  at.  Given  beautiful,  mysterious, 
costly  things  like  pearls,  we  have  no  difficulty  in 
understanding  the  halo  of  secondary  virtues.  Burnt 


68  SECRETS  OF  ANIMAL  LIFE 

to  powder  they  effected  wondrous  cures;  in  the 
mouth  of  the  dead  they  gave  light  to  the  soul ;  they 
became  emblems  of  purity  and  constancy. 

All  over  the  world  some  use  or  other  seems  to 
have  been  made  of  cowrie  shells,  and  in  many  cases 
at  least  there  was  a  cowrie  symbolism.  Perforated 
cowries  are  found  associated  with  the  early  Cro- 
Magnon  men  and  with  pre-dynastic  burials  in 
Egypt;  and  they  were  used  as  money  in  China 
more  than  seven  centuries  B.C.  Now,  cowries 
are  very  beautiful  shells,  they  are  also  very  handy 
for  money,  tokens,  messages,  eyes  for  mummies, 
dice,  balloting,  and  so  forth;  but  there  are  strong 
reasons  for  believing  (with  Mr.  Wilfrid  Jackson 
and  Professor  Elliot  Smith)  that  the  grip  they  have 
taken  of  mankind  has  owed  a  great  part  of  its 
tenacity  to  sex-symbolism  suggested  to  the  many 
by  the  shell's  shape,  and  to  the  few  by  the  way  the 
Hying  animal,  expanding  itself  in  the  shore-pool, 
seemed  to  be  born,  as  it  were,  from  within  the  shell. 
There  \vas  no  manual  of  the  common  objects  of 
the  seashore  in  those  days,  and  to  the  impressionable 
it  was  a  queer  thing  to  see  a  rampant,  horned  and 
hungry  creature  slowly  divulge  itself.  Moreover, 
were  not  these  big  shells  exposed  only  at  the  lowest 
tides,  so  that  from  Mandalay  to  Mexico  they  were 
somehow  linked  to  the  moon,  and  thus  again  to 
women?  We  cannot  help  fancying  that  some  of 
the  early  observers,  in  days  long  before  Aristotle's 
illuminating  insight,  must  have  seen  hermit-crabs 
coming  half  out  of  whelk  shells  and  jerking  back 


THE  CULT  OF  SHELLS  69 

again  with  a  click,  must  have  seen  what  seemed  to 
be  just  the  familiar  slow-going  shells  moving  quickly 
and  even  fighting.  What  a  fine  basis  for  a  doctrine 
of  a  demon  in  the  shell  the  hermit-crab's  tenancy 
would  afford !  But  in  any  case  Aphrodite  was  one 
of  the  earliest  of  man's  deities,  and  the  cowrie 
(Cyprsea)  which  brought  her  to  Cyprus  was  her 
emblem.  It  was  emphatically  the  woman's  shell, 
helping  towards  marriage  and  towards  birth.  It 
brought  good  luck,  it  averted  the  evil  eye,  but 
primarily  it  was  a  symbol  expressive  of  fertility 
and  vitality,  and  had  life-giving,  life-saving  powers. 
In  connection  with  the  custom  of  placing  a  cowrie 
in  the  mouth  of  the  dead,  Professor  Elliot  Smith 
makes  a  very  interesting  note:  "  The  twofold 
significance  of  the  cowrie — the  belief  in  its  vitalizing 
powers  and  its  use  in  currency — led  to  a  confusion 
between  these  two  properties,  and  was  responsible 
for  the  origin  of  a  remarkable  custom.  The  cowrie 
was  placed  in  the  mouth  because  it  was  supposed 
to  be  able  to  animate  the  dead;  but  when  it  came 
to  have  a  new  value  as  currency  this  practice  lost 
its  original  significance,  and  the  use  of  the  shell — 
or  the  actual  metallic  coin  that  superseded  it — 
for  this  purpose  was  rationalized  into  the  belief 
that  it  represented  Charon's  fare  for  ferrying  the 
deceased  to  the  other  world."  According  to  Pro- 
fessor Elliot  Smith  the  whole  of  the  complex  shell 
cult  sprang  from  a  fanciful  suggestiveness  which  led 
a  group  of  primitive  men  to  connect  the  cowrie 
with  sex. 


70  SECRETS  OF  ANIMAL  LIFE 

Few  civilized  men  or  women  see  any  conspicuous 
symbolism  in  the  cowrie;  a  coal-tar  product  has 
taken  the  place  of  Tyrian  purple;  pearls  are  no 
longer  calcined  to  make  priceless  pills;  and  much 
that  has  been  has  passed  away  for  ever.  On  the 
other  hand,  pearls  retain  their  charm;  the  voice  of 
the  shell-trumpet  has  not  yet  ceased;  decorations 
of  shells  are  still  very  common;  and  there  are  few 
children  to  whom  a  beauty-feast  of  shells  appeals 
in  vain.  Probably,  however,  the  most  enduring 
results  of  the  cult  of  shells  have  passed  indistin- 
guishably  into  the  fabric  of  the  human  web  of  life 
— we  mean  "  the  important  part  the  search  for  shells 
has  played  in  the  diffusion  of  the  elements  of  culture 
and  in  the  upbuilding  of  civilization." 


THE  FITNESS  OF  RIGHT  WHALES 

EVERY  age  has  had  its  giants ;  those  of  to-day 
are  the  whales.  For  the  Sperm  Whale  and 
the  Right  Whales  may  be  fifty  feet  long,  and  there 
are  others  even  larger.  The  two  examples  just 
mentioned  suggest  the  familiar  division  of  the 
mammalian  order  Cetacea  into  the  Toothed  Whales 
with  functional  teeth  and  the  Baleen  Whales  with 
whalebone — two  groups  which,  if  they  had  a  com- 
mon ancestry  at  all,  must  have  diverged  very  long 
ago,  for  they  are  now  separated  by  a  multitude 
of  structural  differences.  Among  the  whalebone 
whales  there  are  two  (or  perhaps  three)  called 
"  Right "  simply  because  they  are  the  right  sort  for 
whalers  to  pursue,  being  more  valuable,  as  regards 
baleen  and  blubber,  than  the  Finbacks  and  Hump- 
backs and  other  kinds  which  also  bear  these  precious 
products,  but  in  less  degree.  The  recent  publica- 
tion of  an  admirable  monograph,  Mr.  Glover  M. 
Allen's  Whalebone  Whales  of  New  England  (Bos- 
ton, 1916),  has  prompted  us  to  attempt  an  appreci- 
ation of  the  Right  Whales,  of  which  the  Black 
North  Atlantic  or  Biscay  Whale,  Balcena  glacialis,  is 
now  the  leading  representative. 

First  of  all,  what  an  extraordinary  bundle  of 


72  SECRETS  OF  ANIMAL  LIFE 

adaptations  is  a  whale!  Think  of  the  torpedo-like 
shape,  suited  for  cleaving  the  water;  the  shiny, 
frictionless,  almost  naked  skin;  the  horizontally 
flattened  tail-flukes,  which  serve  as  propellers; 
the  transformation  of  the  fore-limbs  into  paddle- 
like  flippers,  which  are  moved  en  bloc  and  are  mainly 
used  in  balancing;  the  thick  layer  of  blubber  (an 
exaggeration  of  the  subcutaneous  fat  found  in  most 
mammals),  which  retains  the  warmth  of  the  body, 
compensating  for  the  almost  entire  absence  of  hair, 
and  also  helps  to  make  the  whale's  great  bulk  more 
buoyant,  and  by  its  elasticity  to  resist  the  great 
pressure  involved  in  deep  diving;  the  shortening 
of  the  neck  and  the  welding  of  the  vertebrae  of  that 
region;  the  superficial  reduction  of  friction,  illus- 
trated in  the  absence  of  external  ears;  the  dorsal 
position  of  the  valved,  automatically-closing  blow- 
hole or  nostril  (single  in  the  adult  toothed  whales, 
strangely  remaining  in  the  primitive  double  con- 
dition in  the  more  specialized  baleen  whales)  ;  the 
sponginess  of  most  of  the  bones,  making  for  buoy- 
ancy; the  remarkable  networks  of  blood-vessels, 
which  probably  help  respiration  during  the  prolonged 
submersion;  the  relatively  huge  chest-cavity  and 
the  spacious  (though  simple)  lungs,  which  are 
hydrostatic  as  well  as  breathing  organs;  the  usual 
reduction  of  the  offspring  to  one  at  a  time;  and  the 
special  milk-reservoirs  which  give  the  baby  a  big 
mouthful  at  a  gulp.  These  are  more  or  less  obvious 
adaptations,  but  for  one  that  is  obvious  there  are  ten 
that  are  subtle.  There  is,  for  example,  the  arrange- 


THE  FITNESS  OF  RIGHT  WHALES      73 

ment  for  shunting  forward  the  spout-shaped  glottis 
(the  entrance  to  the  windpipe)  so  as  to  project  into 
the  posterior  opening  of  the  nasal  passage  at  the 
back  of  the  mouth.  Thus  the  Baleen  Whale  swim- 
ming with  its  huge  mouth  yawning,  so  as  to  catch 
myriads  of  small  fry,  is  not  itself  drowned.  It  is 
interesting  that  a  very  similar  adaptation  is  seen 
when  the  crocodile  is  drowning  its  prey,  and  when 
the  young  marsupial  in  its  mother's  pouch  is  having 
milk  injected  down  its  gullet. 

The  story  goes  that  a  Yankee  visitor  to  the  Zoo, 
after  a  prolonged  scrutiny  of  the  giraffe,  turned 
away  with  the  remark :  "  I  don't  believe  it."  If 
he  had  been  able  to  give  the  same  attention  to  his 
own  New  England  Right  Whale,  he  might  well  have 
said  the  same.  Black  in  color,  a  Colossus  54 
feet  long,  with  a  head  occupying  about  a  fourth  of 
the  whole,  with  a  neck  as  short  as  the  giraffe's  is 
long  (yet  with  the  same  number  of  vertebrae), 
with  about  250  plates  of  black  baleen  hanging 
down  from  the  roof  of  the  mouth  on  each  side, 
and  sometimes  reaching  a  length  of  7  feet — what 
a  quaint  creature!  The  plates  of  whalebone 
illustrate  one  of  Nature's  evolutionary  methods, 
making  the  new  out  of  the  old,  for  they  are  exag- 
gerations and  cornifications  of  the  transverse  pala- 
tal ridges  to  be  seen  on  the  roof  of  the  mouth  in 
many  other  mammals.  How  striking,  again,  is  the 
apparently  disturbed  topography,  the  nostrils 
far  back  on  the  top  of  the  head,  the  inconspicuous 
eye  away  down  at  the  posterior  corner  of  the  mouth, 


74  SECRETS  OF  ANIMAL  LIFE 

the  ear-hole  a  little  below  and  behind  the  eye  and 
not  wider  than  a  match.  And  there  is  that  curious, 
worn,  warty,  callous  cushion  near  the  front  end  of 
the  snout,  which  goes  by  the  name  of  the  bonnet. 
The  imagination  is  tickled  by  the  sparse  groups 
of  hairs  about  the  snout,  jaws,  and  chin.  They  are 
probably  the  dwindled  residue  of  an  abundant 
primeval  pellage,  for  some  embryo  cetaceans  show 
numerous  hair-rudiments  on  the  anterior  half  of  the 
body.  It  is  possible,  however,  that  the  ancestral 
Cetaceans  had,  even  more  than  hair,  an  armature  of 
scales,  which  was  lost  when  aquatic  habits  were 
acquired.  Some  porpoises  still  show  traces  of 
scales,  and  there  are  some  cetaceans  in  which  no 
vestige  of  hair  has  been  found,  even  before  birth. 
The  hairs  seen  on  the  Right  Whale  are  without 
hair-muscles  or  sebaceous  glands,  but  it  is  appa- 
rently to  some  purpose  that  they  linger,  for  they 
are  extraordinarily  well  innervated,  four  hundred 
nerve-fibers  sometimes  going  to  a  single  hair! 
They  illustrate  the  conservatism  of  evolutionary 
processes,  holding  fast  that  which  is  good,  even  if  it 
be  diverted  to  a  new  function.  It  may  be,  however, 
that  tactility  was  the  primary  function  of  hairs;  we 
see  it  highly  developed  in  the  whisker  hairs  of  many 
mammals,  like  the  cat,  and  less  familiarly  in  various 
types,  in  strategically  disposed  tufts  about  the  hands 
and  feet.  Very  impressive  are  the  deeply  buried 
relics  of  a  hip-girdle  and  thigh-bone,  measuring  in  a 
typical  specimen  of  a  North  Atlantic  Right  Whale 
18  and  5  inches  respectively.  They  show  an 


THE  FITNESS  OF  RIGHT  WHALES     75 

interesting  variability  not  uncommon  in  dwind- 
ling structures,  and  their  long  lingering  may  be 
partly  due  to  the  fact  that  they  afford  insertion 
to  certain  small  muscles.  In  some  unborn  whales 
there  are  two  small  button-like  projections — 
external  hind-limbs  literally  at  a  vanishing-point. 
Absolutely  vestigial  are  the  Right  Whale's  teeth, 
which  never  cut  the  gum  and  are  absorbed  before 
birth.  Yet  there  is  a  first  set  and  a  second  set — as 
in  ourselves. 

There  is  much  that  is  interesting  in  the  sense- 
Organs.  The  eye  is  without  the  usual  eye-cleaning 
third  lid,  its  absence  being  compensated  for  by 
the  continual  washing;  its  practical  absence  in 
our  own  case  is  compensated  for  by  the  frequent 
movements  of  the  upper  eyelid.  The  smelling 
membrane  is  degenerate,  and  there  are  other 
olfactory  deficiencies,  intelligible  enough  in  animals 
of  terrestrial  origin  which  have  come  to  be  habitually 
submerged.  The  outer  ear  passage  is  open  to  the 
water,  and  the  drum  is  so  fixed  that  it  cannot 
vibrate;  it  is  probable  that  the  chief  use  of  the 
whale's  ear  is  in  equilibration,  and  in  making  the 
animal  aware  of  changes  in  the  pressure  of  the  water 
as  it  dives  or  rises.  If  sounds  pass  to  the  ear- 
ossicles  and  the  inner  ear,  it  must  be  through  the 
bones  of  the  skull. 

The  Black  Right  Whale  is  not  gregarious,  but  a 
pair  may  keep  company  for  long,  and  they  may  be 
followed  for  over  a  year  by  their  calf.  The  ordinary 
rate  of  swimming  is  leisurely,  about  four  miles  an 


76  SECRETS  OF  ANIMAL  LIFE 

hour;  and  the  creature  is  fond  of  lying  quietly 
on  the  surface,  perhaps  asleep.  Mr.  Allen  quotes 
an  old  story  of  the  Mayflower's  encounter  in  Cape 
Cod  Bay.  "  We  saw  daily  great  whales,  of  the  best 
kind  for  oil  and  bone,  come  close  aboard  our  ship, 
and  in  fair  weather  swim  and  play  about  us.  There 
was  once  one,  when  the  sun  shone  warm,  came  and 
lay  above  water,  as  if  she  had  been  dead,  for  a  good 
while  together,  within  half  a  musket  shot  of  the 
ship;  at  which  two  were  prepared  to  shoot,  to  see 
whether  she  would  stir  or  no.  He  that  gave  fire  first 
his  musket  flew  in  pieces,  both  stock  and  barrel; 
yet,  thanks  be  to  God,  neither  he  nor  any  man  else 
was  hurt  with  it,  though  many  were  there  about. 
But  when  the  whale  saw  her  time  she  gave  a  snuff, 
and  away."  The  blowing  or  breathing-out  of  hot 
air  occurs  half  a  dozen  or  more  times  in  rapid 
succession,  and  the  "spout,"  consisting  of  water- 
vapor  condensed  into  drops,  plus,  it  may  be,  a 
little  spray  carried  up  by  the  nose-opening  blast, 
may  rise  to  a  height  of  fifteen  feet.  Since  Aristotle 
did  not  think  of  a  whale  as  a  fish,  Milton  was  not 
very  happy  with  his  "  And  at  his  gills  draws  in, 
and  at  his  trunk  spouts  out,  a  sea."  After  a  longer 
or  shorter  period  of  forceful  breathing  the  whale 
dives  (almost  perpendicularly,  so  that  the  flukes 
are  the  last  parts  seen),  and  may  remain  under 
water  for  ten  to  twenty  minutes.  The  Right  Whale 
is  a  dainty  feeder  as  far  as  quality  goes,  for  it  de- 
pends mainly  on  small  crustaceans.  These  are  en- 
gulfed in  the  yawning  cavern  of  the  mouth,  strained 


THE  FITNESS  OF  RIGHT  WHALES      77 

on  the  frayed  inner  edges  of  the  baleen  plates, 
collected  by  the  slow  raising  of  the  fat  and  flabby 
tongue,  and  then  passed  down  into  the  narrow  gullet. 
Whatever  a  Cachalot  may  have  done,  no  Right 
Whale  ever  swallowed  even  a  minor  prophet. 

No  one  has  yet  got  on  terms  of  intimacy  with 
a  Black  Right  Whale,  but  the  general  impression 
seems  to  be  that  it  is  a  gentle  creature,  only  taking 
the  offensive  when  tormented.  It  may  then  break 
a  boat  with  the  impact  of  its  bonnet  or  bumper. 
In  illustration  of  its  endurance  Mr.  Allen  quotes 
the  case  of  a  "  sixty-barrel  "  Right  Whale  which 
was  struck  early  in  the  morning  off  Nantucket,  and, 
heading  out  to  sea,  towed  a  boat  with  six  men  in 
it  for  seven  hours,  and  eventually  got  free.  It  took 
the  men  five  hours'  hard  pulling  to  get  home.  Very 
little  is  known  of  the  breeding  habits,  but  the 
pairing  seems  to  take  place  in  early  summer  and  the 
birth  in  January  or  February.  The  length  of  the 
newborn  calf  is  about  20  feet.  It  is  said  to 
accompany  its  mother  for  at  least  a  year,  being 
weaned  when  between  one  and  two  years  old. 
There  is  no  doubt  as  to  the  parental  attachment  of 
the  mother,  for  she  will  sacrifice  herself  in  the 
attempt  to  rescue  her  offspring,  or  in  the  refusal 
to  leave  it  even  when  dead.  So  far  as  is  known, 
the  North  Atlantic  Right  Whale  has  no  natural 
enemies,  and  they  are  not  known  to  fight  among 
themselves.  It  is  a  long-lived,  dumb,  peace-loving 
creature — too  gentle  to  survive  man's  fright  fulness 
for  long. 


78  SECRETS  OF  ANIMAL  LIFE 

The  particular  whale  we  have  discussed  is  prob- 
ably not  specifically  distinguishable  from  the  Black 
Right  Whale  of  the  South  Atlantic,  but  it  is  quite 
different  from  the  Greenland  Whale  or  Bowhead, 
Balcena  mysticetus,  which  used  to  be  the  object  of 
the  eager  quest  pursued  by  the  whaling  vessels 
that  went  north  from  Dundee,  Aberdeen,  Peter- 
head,  and  similar  ports.  But  that  is  a  story  of  the 
past,  for  the  Greenland  Whale  is  now  a  rarity.  In 
the  fascinating  whale-room  of  the  British  Museum 
we  have  seen  the  enormous  lower  jaws  of  one  of 
the  largest  of  these  magnificent  creatures,  which  was 
killed  in  1887.  It  yielded  26  tons  of  oil  and  26  cwt. 
of  whalebone.  This  Greenland  Whale  is  entirely 
Arctic;  it  is  recorded  as  attaining  a  length  of  70 
feet;  its  head  occupies  a  third  of  the  body;  its  black 
color  is  relieved  by  white  below  the  jaw,  and  there 
are  various  important  structural  differences  between 
it  and  its  non-Arctic  relative.  Dr.  F.  E.  Beddard, 
a  great  authority  on  whales,  tells  us  that  the  Green- 
land Whale  is  "  an  extremely  timid  beast."  It  has 
been  remarked  that  "  a  bird  alighting  upon  its 
back  sometimes  sets  it  off  in  great  agitation  and 
terror."  But  we  do  well  to  be  cautious  with  psy- 
chological adjectives  when  speaking  of  whales. 
For  what  do  we  know  of  the  "  terror "  of  this 
marine  Colossus,  whose  brain  is  of  a  very  high 
order?  The  timidity  is  probably  in  part  a  function 
of  the  frequency  of  whalers.  There  is  unanimity, 
however,  in  the  theoretical  admiration  of  the 
whale's  parental  solicitude.  "  It  would  do  honor," 


THE  FITNESS  OF  RIGHT  WHALES     79 

said  Scoresby,  "to  the  superior  intelligence  of 
human  beings,"  who  will  nevertheless  seek  after 
blubber  and  baleen  until  the  Right  Whales  have, 
alas !  shared  the  fate  of  other  giants  and  passed  into 
the  keeping  of  monographs  and  museums. 


XI 

THE  INTERNAL  ECONOMY  OF  THE  SEA 

i 

NO  one  can  forget  the  first  sight  of  a  big  catcb 
laid  out  for  sale  at  one  of  our  chief  fishing 
ports.  There  are  tons  and  even  miles  of  fishes, 
recently  representing  enormous  locomotor  power  in 
the  sea,  and  soon  to  be  transformed  into  likewise 
enormous,  though  reduced,  power  of  muscle-work 
and  brain-work  on  land.  The  sweepings  go  to  feed 
cattle  and  to  fertilize  the  ground,  and  the  total 
supply  is  in  such  abundance  that  we  stand  wondering 
at  its  continuance  from  day  to  day,  year  in  year 
out.  What  happens  in  the  vast  economy  of  the 
sea?  Who  are  the  producers,  the  consumers,  and 
the  middlemen?  A  well-known  instance  will 
illustrate  our  inquiry — namely,  the  demonstration, 
offered  some  years  ago  by  Dr.  E.  J.  Allen,  the 
Director  of  the  Marine  Biological  Station  at  Ply- 
mouth, that  there  is  a  close  correlation  between  tte 
sunshine  records  for  May  and  the  quantity  of 
mackerel  at  Billingsgate.  The  rationale  of  this  is 
instructive.  Mr.  G.  E.  Bullen  showed  that  there 
is  a  correspondence  between  the  catches  of  mackerel 
during  May  and  the  amount  of  the  Copepod  plank- 
ton (i.e.  small  Crustaceans  of  drifting  habit)  upon 
which  the  mackerel  for  the  most  part  feed.  Then 

80 


INTERNAL  ECONOMY  OF  THE  SEA     81 

Dr.  W.  J.  Dakin  showed  that  the  Copepods,  in 
turn,  feed  largely  on  the  drifting  plant-organisms 
of  the  surface  waters,  such  as  Diatoms,  and  on 
Infusorian-like  animals  called  Peridinians.  But 
the  multiplication  of  these  minute  organisms  de- 
pends in  the  main  on  the  amount  of  sunshine.  So 
that  the  more  sunshine,  the  more  mackerel.  One 
incarnation  follows  another,  Copepod  after  Diatom, 
Mackerel  after  Copepod,  Man  after  Mackerel — an 
illustration  of  Liebig's  luminous  idea  of  the  circula- 
tion of  matter. 

The  producers  of  the  wealth  of  the  sea  are  the 
chlorophyll-possessing  organisms,  most  of  which  are 
indubitable  plants,  though  a  few  incline  to  the 
animal  persuasion.  Of  the  plants  there  are  two 
great  groups:  (a)  the  minute  Algae  of  the  super- 
ficial layers  of  the  open  sea  (the  Phyto-plankton), 
and  (&)  the  sea-grass,  the  larger  seaweeds,  and  the 
attendant  micro-flora,  abounding  in  the  shore  area 
in  the  wide  sense.  Though  many  of  the  seaweeds 
have  also  brown  or  red  pigment,  all  have  chloro- 
phyll. And  by  virtue  of  this — \ve  do  not  know  how 
— they  are  able  to  utilize  the  energy  of  the  sunlight 
to  build  up  the  simple  constituents  of  air  and  sea- 
water  into  complex  organic  products  which  in  turn 
form  the  food  of  animals.  On  this  power  of  photo- 
synthesis depends  the  whole  economy  of  marine  as 
of  terrestrial  life.  It  is  very  generally  believed 
that  the  chief  producers  are  the  minute  and  simple 
Algae  of  the  open  waters  which  form  in  certain 
areas  which  Sir  John  Murray  used  to  call  "  floating 


82  SECRETS  OF  ANIMAL  LIFE 

meadows."  On  the  Beagle  voyage  Darwin  was 
impressed  off  the  coast  of  South  America  with  vast 
tracts  of  water  discolored  by  the  minute  floating 
Algae,  the  "  sea-sawdust  "  of  Captain  Cook's  sailors, 
and  since  the  days  of  the  Challenger  information  in 
regard  to  the  Phyto-plankton  has  grown  apace.  It 
seems  to  be  the  food  of  many  open-sea  animals, 
such  as  small  Crustaceans,  which  again  are  devoured 
by  young  fishes.  The  growth  of  the  sea-meadows 
in  spring  is  thus  as  important  as  the  garment  of 
green  on  the  farmer's  fields.  Professor  Herdman 
of  Liverpool,  a  leading  authority  on  the  biology  of 
the  sea,  cites  the  calculation  that  a  Diatom  "  less 
than  the  head  of  a  pin,  dividing  into  two  at  the 
normal  rate  of  five  times  in  the  day,  would  at  the 
end  of  a  month  form  a  mass  of  living  matter  a 
million  times  as  big  as  the  sun.  The  destruction 
that  keeps  such  a  rate  of  reproduction  in  check 
must  be  equally  astonishing."  It  should  be 
noticed,  however,  that  considerable  evidence  is 
accumulating  in  support  of  the  view  that  the 
minute  constituents  of  the  Phyto-plankton  are  even 
more  important  in  their  death  than  in  their  life. 
For  when  they  are  killed  by  changes  of  temperature 
and  the  like,  or  when  they  reach  the  end  of  their 
natural  tether,  they  add  to  the  valuable  organic 
detritus  which  remains  in  suspension  in  the  water 
or  sinks  to  the  floor  of  the  sea.  To  this  accumula- 
tion of  organic  debris  very  important  contributions 
are  also  made  from  the  littoral  belt  of  seaweed  and 
sea-grass.  Indeed,  recent  investigations  by  two 


INTERNAL  ECONOMY  OF  THE  SEA     83 

Danish  naturalists,  Petersen  and  Jensen,  show  that 
the  organic  matter  of  the  sea-floor  in  the  sheltered 
waters  of  fjords  and  bays  is  mainly  due  not  to  the 
sinking  down  of  the  minute  Plankton  organisms, 
but  to  the  detritus  of  the  sea-grass  (Zostera)  and 
its  associates  in  shallow  water.  This  is  of  enormous 
practical  importance,  since  it  is  in  man's  hands  to 
cultivate,  if  need  be,  the  littoral  vegetation,  and 
thus  cast  bread  upon  the  waters,  to  be  gathered 
again  after  many  days.  But  aquiculture  is  not  yet 
a  pressing  need. 

As  to  a  heresy  started  some  years  ago  by  Profes- 
sor Putter,  that  sea-water  contains  large  quantities 
of  dissolved  organic  matter- — a  sort  of  fundamental 
"  stock  "  of  the  sea-soup — and  that  this  accounts 
for  the  sustenance  of  many  marine  animals  whose 
food  supply  has  been  confessedly  difficult  to  dis- 
cover, it  cannot  be  said  to  have  been  confirmed 
by  further  investigation.  In  fact,  recent  work  by 
Professor  Benjamin  Moore  and  others  at  Port  Erin 
Biological  Station  is  quite  against  it.  The  prob- 
ability is  that  sufficient  importance  has  not  been 
attached  to  the  nutritive  role  played  by  the  organ- 
isms of  the  Dwarf  Plankton  (Nanno-plankton), 
which  abound  beyond  telling  in  the  open  sea,  and  are 
so  extremely  minute  that  they  pass  through  the 
invisible  pores  of  the  finest  silk  cloth  used  in  tow- 
netting.  There  is  thus  no  reason  to  depart  from 
the  conclusion  that  the  producers  in  the  economy 
of  the  sea  are  the  chlorophyll-possessing  plants, 
both  of  high  and  low  degree,  and  such  small  animal 


84  SECRETS  OF  ANIMAL  LIFE 

organisms  as  have  stolen  their  secret  of  photo- 
synthesis. But  it  is  time  to  add  the  statement 
that  a  large  proportion  of  the  animals  of  the  sea- 
floor  live  on  dead  detritus,  which  is  formed  by 
contributions  from  three  sources — the  superficial 
Plankton,  the  fauna  and  flora  of  the  shore,  and 
what  is  borne  down  by  rivers.  We  shall  return  to 
this  in  our  next  study. 

The  natural  consumers  of  the  wealth  of  the  sea 
are  the  animals,  but  these  are  not  all  on  the  same 
platform.  First,  there  are  true  carnivores,  like 
most  fishes,  all  cuttlefishes,  many  Gasteropods 
(like  whelks),  many  crabs,  most  starfishes,  and  so 
on  down  to  sea-anemones.  Second,  there  are 
vegetarians,  like  periwinkles  and  limpets,  on  the 
shore,  and  some  of  the  open-sea  animals  like  the 
Copepod  Crustaceans.  Third,  there  is  an  enormous 
multitude  depending  mainly  on  crumbs  or  detritus. 
This  classification  is  not,  of  course,  to  be  taken  too 
rigidly,  for  it  will  be  readily  understood  that  many 
a  marine  carnivore  may  also  utilize  carneous  debris 
— just  as  a  Golden  Eagle,  with  a  preference  for 
fresh  grouse,  does  not  always  hold  carrion  in  dis- 
dain. Similarly,  some  marine  vegetarians  are  not 
too  scrupulous  as  to  the  constituents  of  the  sea-soup 
they  enjoy.  The  probability  is  that  the  distinction 
between  carnivore  and  vegetarian  is  not  so  important 
as  that  between  animals  with  and  animals  without 
hard  prehensile  and  chewing  mouth-parts.  This,  like 
Professor  William  James's  division  of  mankind  into 
tough-minded  and  tender-minded,  goes  very  deep. 


INTERNAL  ECONOMY  OF  THE  SEA     85 

We  may  speak  of  it  as  the  distinction  between 
the  hard-mouthed  and  the  soft-mouthed,  and  it  is 
radical.  But  to  follow  it  up  would  take  us  too  far 
from  our  present  theme. 

The  middlemen  are  Bacteria,  which  get  involved 
in  so  many  different  ways  in  the  business  of  life. 
Salt  is  well  known  to  be  antithetic  to  them,  but  it 
has  riot  kept  them  out  of  the  sea,  where  they  have 
more  than  one  important  role  to  play.  Thus  some 
are  putrefactive,  breaking  down  the  dead  bodies 
of  animals  and  plants,  and  the  excreta  of  animals, 
reducing  them  to  carbon  -  dioxide,  ammonia, 
ammoniates,  and  the  like,  which  may  re-enter  the 
field  of  life  by  forming  food  for  Algae.  Microbes 
of  this  sort  are  for  ever  making  a  clean  thing  out 
of  an  unclean.  But  there  are  others  which  play  a 
subtler  part,  by  changing  the  ammoniacal  nitrogen 
into  nitrites,  and  others  which  carry  on  this  work 
by  completing  the  oxidation  into  nitrates.  And  as 
nitrites  are  more  available  for  the  nutrition  of  plants 
than  are  ammoniacal  compounds,  and  as  nitrates 
are  more  available  than  nitrites,  we  see,  as  they  said 
of  old  time,  how  well  this  world  is  governed.  It  is 
not  to  be  forgotten,  however,  that  there  are  many 
denitrifying  bacteria  which  work  the  wrong  way  by 
reducing  nitrates  to  nitrites,  nitrites  to  ammonia, 
and  ammonia  to  free  nitrogen.  Professor  Brandt 
has  suggested  as  a  reason  for  the  remarkable  fact 
that  the  cold  Polar  waters  are  richer  in  Plankton 
than  tropical  seas,  that  the  higher  temperature 
favors  the  action  of  denitrifying  bacteria,  which 


86  SECRETS  OF  ANIMAL  LIFE 

therefore  flourish  so  abundantly  that  the  supply  of 
available  nitrogenous  food  for  the  Phyto-plankton 
is  greatly  lessened.  According  to  Sir  John  Murray 
and  Professor  Jacques  Loeb,  the  reason  is  rather 
that  low  temperature  slows  the  vital  processes  and 
increases  the  length  of  life,  so  that  several  gener- 
ations of  Plankton  organisms  are  living  at  the  same 
time  in  the  colder  waters.  It  is  probable  that  both 
views  are  correct. 

It  is  hardly  necessary  to  say  that  the  analogy  of 
producers,  consumers,  and  middlemen  should  not 
be  pressed  too  hard.  Thus  it  is  quite  useful  to 
follow  a  recent  investigator,  Dr.  Blegvad,  in  regard- 
ing the  detritus-eating  animals  as  producers  in 
relation  to  the  carnivores,  just  as  fishes  are  pro- 
ducers in  relation  to  the  supreme  carnivore  Man. 
Bivalves  and  other  animals  which  feed  at  a  low 
level  on  minute  debris  are  making  available  to  any 
creature  that  can  eat  them  supplies  of  energy  which 
would  otherwise  be  wasted.  Plaice  in  the  Kattegat 
are  very  fond  of  lancelets,  which  subsist  on  detritus 
particles;  so  that  in  respect  to  the  plaice  the 
lancelet  is  a  producer  or  a  middleman.  The  main 
idea  is  that  of  the  circulation  of  matter,  or  of  what 
Sir  John  Murray,  who  did  so  much  to  make  Oceano- 
graphy a  science,  called  "  the  never-ending  cycle." 
The  Algae  find  nourishment  mingled  with  the  water 
that  bathes  them,  and,  using  chlorophyll  to  "  con- 
jure with  the  sunbeams,"  they  build  up  organic 
compounds  from  inorganic  constituents.  Vegetable 
proteins  are  thus  formed,  and  when  these  are  eaten 


INTERNAL  ECONOMY  OF  THE  SEA      87 

by  animals  they  are  raised  to  a  still  higher  incar- 
nation as  animal  proteins.  But  when  the  plant  or 
animal  dies  the  complex  organic  substances  are 
broken  down  through  the  agency  of  bacteria  into 
simple  constituents  once  more,  and  some  of  these 
being  utilized  by  plants  may  enter  again  into  the 
circle  of  life.  Shakespeare,  with  his  prescience, 
spoke  of  what  might  happen  to  the  dust  of  Caesar, 
but  it  was  only  a  vague  vision  that  he  can  have 
had  of  the  long  nutritive  chains,  with  quaint 
sequences  like  those  of  "  The  House  that  Jack 
built,"  which  connect  Diatoms  and  debris  with 
fishes  and  man.  As  Professor  Herdman  tells  us, 
man  eats  the  cod,  which  in  turn  may  feed  on  the 
whiting,  and  that  on  the  sprat,  and  the  sprat  feeds 
on  Copepods,  which  again  depend  on  Peridinians 
and  Diatoms.  Most  of  the  nutritive  chains  bring  us 
through  Copepods  to  sea-grass  and  seaweeds,  to 
Diatoms  and  debris.  For  so  the  world  goes  round, 
and  such  are  the  incarnations  of  the  sea. 


XII 
SEA-MEADOWS 

EXPLORERS  of  the  sea  have  described  "  float- 
ing meadows,"  consisting  of  countless 
millions  of  minute  or  microscopic  plants,  extending 
for,  perhaps,  a  hundred  miles  without  interruption. 
These  simple  plants,  and  the  minute  single-celled 
animals  often  associated  with  them,  afford  food  for 
Crustaceans  and  other  small  fry,  which,  in  turn,  are 
eaten  in  great  numbers  by  dainty  feeders  like 
mackerel.  A  few  fishes,  such  as  sardines,  feed  in 
great  part  directly  on  unicellulars.  There  is  no 
doubt  that  the  minute  inhabitants  of  the  superficial 
waters  are  directly  or  indirectly  of  great  importance 
as  food  for  creatures  of  larger  growth,  such  as 
mackerel  and  herring,  which,  in  turn,  mean  much 
to  man.  Dissolved  organic  compounds,  sometimes 
rising  from  the  floor  of  the  sea,  sometimes  produced 
near  the  surface,  may  be  utilized  by  larger  animals 
(to  what  extent  we  do  not  yet  know),  or  may  be 
reclaimed  for  utilization  by  the  varied  and  often 
subtle  agencies  of  bacteria.  So  much,  in  passing, 
for  the  surface  population;  but  what  of  the  food- 
supply  along  the  floor  of  the  sea? 

In  answering  this  question  it  has  been  usual,  as 
we  have  seen  in  the  preceding  study,  to  give  promi- 


SEA-MEADOWS  89 

nence  to  the  part  played  by  the  down-sinking  of 
minute  (Plankton)  organisms  killed  or  worn  out 
at  the  surface,  and  there  is  no  reason  to  disregard 
this  factor.  It  is  probably  of  fundamental  impor- 
tance for  the  immense  areas  which  may  be  called 
more  or  less  abyssal,  for  these,  being  far  beyond  the 
limit  of  illumination,  cannot  have  any  autoch- 
thonous plants  able  by  photo-synthesis  to  build  up 
complex  carbon-compounds  from  simple  constitu- 
ents in  the  water.  But  in  the  relatively  shallow 
illumined  waters  near  shore  the  economy  is  different, 
and  it  seems  that  great  importance  must  be  ascribed 
to  what  may  be  called  "  sea-meadows/' — the  dense 
growths  of  sea-grass  (Zostera),  a  veritable  flower- 
ing plant,  and  of  attached  seaweeds,  large  and  small, 
from  the  great  bladder-wracks  and  laminarians  to 
the  small  tufts  of  the  palatable  "  carrageen "  or 
Irish  moss.  Without  depreciating  the  role  of  the 
minute  Plankton  organisms  which  may  sink  down 
from  the  surface,  we  wish  to  state  the  case  which 
Professor  C.  G.  Joh.  Petersen  has  recently  presented 
in  an  interesting  report  (1918)  to  the  Danish  Board 
of  Agriculture,  which  at  any  rate  shifts  the  emphasis 
to  the  sea-meadows.  It  need  hardly  be  said  that 
Danish  waters  are  much  less  heterogeneous  than 
those  around  British  shores. 

In  the  relatively  shallow  Danish  waters  the  sea- 
bottom  consists  of  vast  plains  of  sand,  mud,  or  clay, 
with  transitions  between  these;  and  almost  every- 
where except  in  the  deepest  and  calmest  hollows 
there  are  scattered  stones  of  all  sizes  carrying  a 


90  SECRETS  OF  ANIMAL  LIFE 

distinctive  population  of  their  own.  From  the 
shore  to  a  depth  of  two  or  three  fathoms  are  the 
meadows  of  the  sea-grass,  with  true  roots  and 
flowers  and  very  long  ribbon-like  leaves,  familiar  as 
a  packing  and  stuffing  material  and  as  a  covering  for 
Italian  flasks  of  wine  or  oil.  Mixed  with  this  Zostera 
are  the  seaweeds  proper,  attached  but  without 
true  roots,  enlivening  the  grass-green  with  beautiful 
reds,  browns,  and  olives.  Farther  out  the  sea- 
weed vegetation  thins,  until  it  disappears  at  a 
depth  of  about  twenty-five  fathoms.  It  is  a  crowded 
vegetative  area,  able  to  support  a  crowded  animal 
life;  the  waving  sea-grass  is  often  as  thick  as  the 
stems  in  a  cornfield,  and  Professor  Petersen  notes 
that  the  total  annual  yield  in  Danish  waters  is  over 
8000  million  kilograms  of  dry  matter,  about  four 
times  the  quantity  of  hay  produced  in  a  year  in 
Denmark.  This  suggests  further  utilization — the 
Zostera  is  already  used  for  fodder,  for  paper-mak- 
ing, for  making  explosives,  and  in  other  ways — but 
sea-grass  is  a  difficult  harvest  to  reap,  and  perhaps 
its  greatest  value  is  the  indirect  one,  that  it  forms  a 
basal  food  supply  for  animals  on  which  many  food 
fishes  mostly  depend.  For  what  Professor  Petersen 
and  his  colleagues  have  discovered  is  that  the  surface 
of  the  mud  (or  clay  farther  from  shore)  is  covered 
by  a  thin  layer  of  detritus  of  very  nutritive  quality, 
and  that  this  is  mainly  produced  by  fragments  of 
sea-grass  and  littoral  seaweeds,  the  downward  sink- 
ing Plankton  counting  for  little.  Examination  of 
the  stomach  contents  of  common  non-predatory 


SEA-MEADOWS  91 

animals  shows  that  the  food  consumed  consists  very 
largely  of  this  valuable  debris.  Thus  the  main 
food  of  oysters  and  other  bivalves  is  vegetable  dust 
"  which  is  found,  either  in  suspension  in  the  water, 
or  deposited  as  the  thin  upper  layer  of  the  bottom 
itself,  lifting  and  spreading  at  times  in  stormy 
weather,  but  only  to  be  precipitated  anew  later  on." 
Some  of  Professor  Petersen's  statistics  are  very 
interesting.  His  valuation  of  the  sea-meadows  of 
Danish  waters  inside  the  Skaw  shows  a  total  of 
24  million  tons  for  the  plants,  5  million  tons  for 
those  animals  that  are  "  useless  "  both  directly  and 
indirectly,  I  million  tons  for  the  "  useful' '  forms 
that  furnish  or  may  furnish  food  for  fishes,  and  only 
some  few  thousands  of  tons  (5  to  7000)  for  each  of 
the  short  list  of  valuable  food  fishes,  such  as  plaice 
and  cod.  Starfishes  make  up  25,000  tons,  more 
than  all  the  important  food  fishes  lumped  together, 
while  crabs  and  Gastropods  amount  to  no  less  than 
50,000  tons.  We  see  that  food-fishes  form  only 
an  insignificant  part  of  the  total  stock  of  animal 
life  in  waters  like  the  Kattegat.  The  reason  is  to 
be  found  in  the  relations  that  govern  the  circulation 
of  matter  or  the  metabolism  of  the  sea.  To  make  a 
pound  of  cod  requires  10  Ib.  of  whelk  or  buckie; 
to  make  a  pound  of  buckie  requires  10  Ib.  of 
worms;  to  make  a  pound  of  worm  requires  10  Ib. 
of  vegetable  matter,  which  may  be  given  in  the 
form  of  dust!  So  a  pound  of  a  carnivorous  fish 
like  a  cod  requires  1000  Ib.  of  sea-grass.  If  there 
be  fewer  links  in  the  House-that-jack-built  nutri- 


92  SECRETS  OF  ANIMAL  LIFE 

live  chain,  the  pound  of  flesh  will  be,  so  to  speak, 
cheaper.  Thus  a  pound  of  plaice  is  said  to  require 
to  begin  with  only  100  Ib.  of  vegetable  material. 
But  the  basal  fact  is  clear  that  just  as  all  flesh  is 
"  grass,"  so  sooner  or  later  all  fish  is  "  seaweed." 

In  spite  of  the  old  saying,  Vitior  alga, — "  More 
worthless  than  seaweed," — these  humble  plants  have 
many  uses,  e.g.  in  making  mannite,  mucilage,  and 
manure.  The  nutritive  value  of  seaweed  is,  indeed, 
an  old  story;  the  streets  of  Edinburgh  used  to 
resound  with  the  shrill  cry  of  the  fishwives — 
" Wha'll  buy  dulse  and  tangle?"  but  what  science 
has  shown  is  that  the  indirect  importance  is  much 
greater  than  the  direct. 

It  is  plain,  then,  that  fishes  are  far  from  being* 
economical  to  produce.  They  are  like  a  super- 
structure that  requires  a  very  broad  and  costly 
foundation.  The  quantity  of  humbler  life  that 
makes  the  food-fishes — almost  wholly  carnivorous — 
possible  is  enormous;  and  the  estimate  has  to  be 
increased  \vhen  we  remember  that  a  great  proportion 
of  the  weight  of  an  animal  which  a  fish  devours 
may  be  quite  useless — e.g.  the  water  in  its  tissues 
and  the  shell  of  lime.  Thus  \ve  are  naturally  led  to 
Professor  Petersen's  important  practical  conclusion 
that  the  quantity  of  fishes  which  an  area  of  sea 
can  support  is  anything  but  unlimited.  In  some 
restricted  bays,  indeed,  he  found  strong  reasons  for 
suspecting  that  the  limit  had  been  reached.  That 
this  limit  is  a  generous  one  is  an  important  fact  for 
man,  for  the  Danish  fishermen  took  about  60,000 


SEA-MEADOWS  93 

tons  of  fishes  off  their  coasts  in  1915,  which  is  more 
than  twice  the  total  export  of  eggs  from  the  country. 
And  fishes  have  not  to  be  fed  in  the  same  sense  as 
poultry.  The  question  arises,  however,  whether 
the  system  of  interrelations  established  in  the  sea 
cannot  be  improved  so  as  to  yield  a  smaller  number 
of  useless  and  a  larger  number  of  useful  animals. 
An  interesting  question  indeed,  but  no  naturalist 
who  realizes  the  implications  of  "  the  web  of  life  " 
will  be  in  a  hurry  to  do  more  than  experiment  on  a 
small  scale.  The  balance  of  nature  is  not  to  be 
tampered  with  impetuously. 

Utilitarian  considerations  apart,  the  sea-meadows 
are  of  great  scientific  interest.  In  his  Voyage  of 
the  "Beagle"  Darwin  was  impressed  by  the  Kelp 
(Macrocystis  pyrifera)  and  its  animal  associates. 
He  writes :  "  The  number  of  living  creatures  of 
all  orders  whose  existence  intimately  depends  on 
the  Kelp  is  wonderful.  A  great  volume  might  be 
written  describing  the  inhabitants  of  one  of  these 
beds  of  seaweed.  ...  I  can  only  compare  these 
aquatic  forests  of  the  Southern  Hemisphere  with  the 
terrestrial  ones  in  the  inter-tropical  region.  Yet  if 
in  any  country  a  forest  was  destroyed,  I  do  not  be- 
lieve nearly  so  many  species  of  animals  would  perish 
as  would  here,  from  the  destruction  of  the  Kelp." 

The  succession  of  incarnations  from  sea-grass 
to  fisherman  gives  one  a  vivid  impression  of  the 
universal  flux;  there  is  a  fascinating  variety  of  ani- 
mal-communities— Professor  Petersen  distinguishes 
eight  distinctive  associations,  each  with  an  economic 


94  SECRETS  OF  ANIMAL  LIFE 

regime  of  its  own;  the  struggle  for  existence  is 
intense;  the  life-saving  adaptations  and  shifts  for 
a  living  are  endless ;  "  passions  there,  laws,  pursuits, 
tribes/'  as  Walt  Whitman  said  in  his  "  World  below 
the  Brine."  For  it  is  to  the  region  of  the  sea- 
meadows  rather  than  to  the  deep  sea,  that  most 
of  that  vivid  picture  applies: 

The  World  below  the  brine, 

Forests  at  the  bott9m  of  the  sea — the  branches  and  leaves, 

Sea-lettuce,   vast   lichens,    strange   flowers   and   seeds — the 

thick  tangle,  the  openings,  and  the  pink  turf, 
Different  colors,  pale  grey  and  green,  purple,  white,  and 

gold — the  play  of  light  through  the  water, 
Dumb    swimmers    there   among   the    rocks— coral,    gluten, 

grass,  rushes — and  the  aliment  of  the  swimmers, 
Sluggish    existences    grazing   there,    suspended,    or    slowly 

crawling  close  to  the  bottom. 

This  and  more  also  will  be  subscribed  to  by  all  who 
have  spent  a  summer  afternoon  drifting  here  and 
there  over  the  sea-meadows,  peering  into  the 
crowded  life  below,  enjoying  the  play  of  color, 
lifting  now  and  again  a  leaf  of  sea-grass — some- 
times 6  feet  long — to  discover  how  many  small 
creatures  were  browsing  there,  or  raising  mare 
adventurously  a  stone  from  the  bottom  to  see  what 
is  meant  by  an  "  epifauna,"  sometimes  a  dozen  dif- 
ferent kinds  of  creatures  living  together  in  moving 
equilibrium.  "  But  what  an  endless  task  have  I  on 
hand  to  count  the  sea's  abundant  progeny,  whose 
fruitful  seede  farre  passeth  those  on  land  ...  so 
fertile  be  the  flouds  in  generation,  so  huge  their 
numbers,  and  so  numberlesse  their  nation." 


xiti 

FRANKINCENSE  AND  MYRRH 

WHEN  we  come  in  the  sunshine  upon  a  patch 
of  mown  grass  with  a  good  proportion  of 
Sweet  Vernal,  we  experience,  with  all  normally 
constituted  mankind,  a  great  sensory  satisfaction. 
The  fragrance  is  delicate,  complex,  and  restful ;  for 
the  moment  all  is  right  with  the  world.  But  why 
it  should  be  so,  it  is  difficult  to  tell.  The  odor- 
iferous substances  in  plants  are  usually  ethereal 
oils  and  resins,  by-products  or  end-products  of 
certain  vital  chemical  processes.  Little  is  known 
of  their  physiological  significance  in  the  economy 
of  the  plant;  most  of  them  rank  as  waste-products. 
But  should  one  of  them  turn  out  to  be  very  attractive 
to  the  olfactory  sense  of  welcome  insect-visitors, 
such  as  bees,  or  very  repellent  to  voracious  enemies, 
such  as  snails,  then  it  will  tend  to  acquire  survival- 
value,  and,  other  things  equal,  to  grow  in  strength. 
We  have  to  think  of  all  these  new  departures — for 
they  must  all  have  had  their  beginnings — as  like 
tendrils  probing  the  unknown.  If  they  get  no 
encouragement  they  come  to  little,  except  in  so 
far  as  they  are  the  necessary  corollaries  of  indis- 
pensable antecedent  processes;  if  they  find  a 
support  they  grow  strong.  Thus  some  of  the 

95 


&6  SECRETS  OF  ANIMAL  LIFE 

odoriferous  substances  of  plants  are  justified  by 
their  protective  value,  and  others  by  their  attractive 
value,  while  of  many  it  must  be  simply  admitted 
that  their  significance  is  internal  and  chemical, 
sometimes  perhaps  no  more  than  that  of  the  waste- 
products  in  a  manufactory,  and  that  their  quality 
of  olfactory  stimulation  has  not  been  turned  to  any 
account.  They  are  the  ashes  of  the  living  fires, 
yet  as  we  sniff  the  perfumed  air  in  which  quintillions 
of  aromatic  particles  are  hurrying  past  us,  here  from 
gorse  and  hawthorn,  there  from  woodruff  and  sweet 
vernal  grass,  we  cannot  but  ask  whether  this  multi- 
tudinous aerial  excretion  may  not  have  some 
physiological  significance  in  the  economy  of 
creatures  which  are,  as  compared  \vith  animals,  con- 
spicuously without  arrangements  for  getting  rid  of 
their  waste  products.  May  not  this  volatilization  of 
the  ethereal  oils  help  to  keep  the  floral  fire  from 
being  smothered  in  its  own  ashes? 

In  this  medley  of  odors,  whiffs  of  brier  rose  and 
lady's  bedstraw,  honeyed  clover  and  soporific 
myrrh,  the  idea  that  rings  in  the  mind  like  a  bell 
is  Individuality,  Specificity,  Uniqueness.  All  flesh 
is  not  the  same  flesh,  and  each  flower's  fragrance 
is  its  own  and  no  other's.  Some  five  hundred 
different  aromatic  compounds  have  been  distin- 
guished, such  as  the  aminoid  in  hawthorn,  the 
benzoloids  in  mignonette  and  violets,  the  paraffin- 
oids  in  geranium  and  rose,  the  turpenoids  in  orange 
and  lavender,  each  group  including  many  specifi- 
cally different  kinds,  indices  of  the  individuality 


FRANKINCENSE  AND  MYRRH          97 

of  the  chemical  processes  in  each  plant.  Strangest 
of  all  are  the  indoloids  in  Aroids,  Aristolochia, 
and  Rafflesia,  which  attract  carrion-loving  flies 
and  are  said  to  arise  from  the  breaking  down  of 
proteids.  Besides  the  specificity  of  chemical  com- 
position and  scent  there  are  other  individual 
peculiarities,  for  some  plants  have  fragrant  leaves, 
while  in  others  the  incense  is  made  only  by  the 
petals;  some,  like  the  grass  of  Parnassus,  are  sweet- 
scented  only  in  the  sunshine,  while  others,  like  the 
evening  campion,  wait  for  the  night.  The  nauseat- 
ing smell  of  the  corn-spurrey  is  particularly  strong 
after  a  summer  shower. 

The  production  of  odoriferous  substances  is 
characteristic  of  flowering  plants,  but  by  no  means 
confined  to  them;  it  is  familiar,  for  instance,  in  the 
males  of  many  butterflies  and  moths.  Peculiarly 
transformed  scales  on  the  \vings,  or  tufts  of  hairs 
on  other  parts  of  the  body,  exude  an  aromatic 
secretion,  the  secondary  significance  of  which  is 
that  it  appeals  to  the  female  insects.  Some  of 
the  scents  produced  by  male  Lepidoptera  are 
pleasant  to  the  human  olfactory  sense,  resembling 
musk,  mint,  vanilla,  honey,  and  the  like;  others 
are  suggestive  of  mice  and  bats.  It  is  interest- 
ing to  notice  that  in  some  cases,  though  glandular 
scales  are  abundantly  present,  we  cannot  smell 
anything,  which  probably  means  that  the  aromatic 
substances  lie  outside  our  range  of  olfactory  stimu- 
lation, just  as  many  rays  of  light  lie  beyond  our 
range  of  vision.  It  may  be  recalled  that  the  volatile 


98  SECRETS  OF  ANIMAL  LIFE 

poison  of  toads,  known  as  phrynin,  inflames  the 
olfactory  membrane  if  we  sniff  it,  yet  there  is  no 
smell.  It  is  certain  that  the  world  is  full  of  scents, 
as  of  sounds,  to  which,  happily  or  unhappily,  our 
senses  are  not  attuned.  There  is  experimental 
evidence  of  a  highly  specialized  sense  of  smell  in 
many  insects,  such  as  hive-bees,  and  its  practical 
value  to  flower-visitors  is  obvious.  According  to  a 
recent  investigator,  a  drone  bee  has  2600  olfactory 
pores,  and  responds  to  a  suddenly  introduced 
fragrance,  such  as  oil  of  thyme,  in  2.9  seconds;  a 
worker  had  2200  pores,  and  responds  in  3.4  seconds ; 
and  a  queen  has  1800  pores,  and  responds  in  4.9 
seconds. 

Odoriferous  substances  are  formed  in  many  in- 
sects besides  moths  and  butterflies,  as  every  one 
knows  in  the  case  of  cockroaches  and  bugs,  and  it  is 
possible  that  they  have  primarily  to  do  with  waste- 
products,  just  as  the  white  and  yellow  color  of 
some  butterflies  is  due  to  uric  acid  or  derivatives 
thereof — a  literal  beauty  for  ashes.  Secondarily, 
however,  the  scents  of  insects  have  come  to  have  a 
significance  in  mating,  and  they  are  often  confined 
to  the  males.  They  are  comparable  to  the  musky 
odors  of  musk-deer,  musk-ox,  and  crocodile,  and 
to  other  scents  in  many  male  mammals  and  in  some 
male  reptiles.  The  presence  of  scent-glands  in  many 
male  bats  is  an  obviously  useful  adaptation  to 
crepuscular  conditions;  that  there  should  be 
practically  no  development  of  the  kind  in  birds  is 
naturally  correlated  with  their  poor  sense  of  smell. 


FRANKINCENSE  AND  MYRRH          99 

Where  scent-glands  occur  in  both  sexes  among 
mammals,  they  may  contribute  to  a  mutual  sex- 
appeal,  or  they  may  facilitate  the  recognition 
of  kindred  and  of  well-frequented  roadways.  In 
certain  cases  they  may  be  protectively  repellent: 
thus  shrews  are  in  some  measure  saved  from  cats 
by  the  odoriferous  gland  which  runs  along  the  side 
of  their  body.  In  the  homing  of  many  ants  odor- 
iferous particles  serve  as  guide-posts,  and  the 
accuracy  with  which  a  dog  tracks  his  master's 
footsteps  is  one  of  the  marvels  of  everyday  life. 
Of  the  chemistry  of  animal  scents  little  is  known, 
but  in  insects  they  include  fatty  acids,  even  salicylic 
acid,  free  iodine,  and  in  a  common  millipede  of 
greenhouses  actually  hydrocyanic  acid — all  of  them 
holding  out  a  promise  to  the  investigator. 

The  sense  of  smell  is  nearest  that  of  taste,  and  the 
two  probably  merge  in  some  of  the  fishes.  In 
smelling  we  are  affected  by  minute  particles  which 
are  dissolved  on  the  moist  surface  of  the  olfactory 
membrane  in  our  nostrils;  in  tasting  we  are 
affected  by  substances  similarly  dissolved  on  the 
taste  papillae  of  our  tongue.  We  can  smell  ex- 
tremely dilute  solutions  which  we  cannot  taste. 
Thus  a  very  minute  amount  of  material  coming 
from  a  far-off  object  is  sufficient  to  stimulate  our 
sense  of  smell,  but  insufficient  to  affect  taste. 
Therefore,  as  Professor  Sherrington  has  put  it, 
our  olfactory  organs  are  "  distance-receptors,"  as 
compared  with  our  gustatory  organs.  In  both 
cases  the  stimulus  is  due  to  the  chemical  action  of 


100  SECRETS  OF  ANIMAL  LIFE 

a  foreign  body,  and  the  same  is  true  of  the  general 
chemical  sense,  best  known  in  fishes,  which  has  its 
seat  on  various  parts  of  the  skin  and  detects  diffus- 
ing substances. 

It  has  been  widely  assumed  that  the  general 
chemical  sense  represents  the  primitive  irritability 
from  which  smell  and  taste  have  been  evolved, 
but  the  work  of  Professor  G.  H.  Parker  points 
rather  to  the  conclusion  that  "  the  most  primitive  of 
the  chemical  sense  organs  in  the  vertebrate  is  the  ol- 
factory organ,  followed  by  that  of  the  common 
chemical  sense,  from  which  the  final  organ  in  the 
series,  the  organ  of  taste,  arose."  It  is  certain 
that  the  olfactory  nerve-cell,  characteristic  of  back- 
boned animals,  such  as  is  pleasantly  stimulated 
when  we  detect  from  far  inland  the  tang  of  the  sea, 
closely  resembles  that  of  many  humble  backboneless 
animals,  such  as  is  stimulated  when  the  sea-anemone 
in  the  aquarium  stretches  its  tentacles  towards  the 
food  which  we  have  dropped  in  at  a  distant  corner. 
There  is  no  telling  why  the  stimulation  produced 
in  us  when  we  tread  on  the  wild  thyme  is  so  very 
pleasant  and  why  that  produced  by  the  corn-spurrey 
is  so  very  unpleasant,  the  one  flower  is  just  as 
beautiful  as  the  other;  but  it  is  possible  that  careful 
inquiry  might  carry  us  beyond  the  bare  facts. 
Certain  scents  have  a  stimulating  effect  on  the  pulse, 
increasing  our  feeling  of  vitality,  and  similar  scents 
which  have  no  such  physiological  virtue  may  by 
association  acquire  vicarious  merit.  Similarly, 
some  unpleasant  natural  odors,  like  that  of  hound's 


FRANKINCENSE  AND  MYRRH        101 

tongue  and  that  of  mice,  may  turn  out  to  have  an 
actual  depressing  effect,  which  may  be  emphasized 
by  association  if  they  call  up  the  memories  of  the 
fatigue  and  stupefaction  induced  by  organic 
particles  in  crowded  rooms  and  filthy  streets. 

It  is  usually  said  that  man's  pleasure  in  the 
fragrant  and  the  palatable  has  no  correlated  aesthetic 
emotion  like  that  which  accompanies  looking  at 
the  beautiful  or  listening  to  music.  But  we  doubt 
the  accuracy  of  this  hard-and-fast  statement,  and 
are  inclined  to  think  that  the  difference  is  in  degree, 
not  in  kind.  One  of  the  difficulties  is  in  trying  to 
discriminate  between  the  immediate  effect  of  certain 
fragrances  and  that  of  the  pleasant  associations 
which  they  arouse.  And  again,  while  we  agree, 
of  course,  with  Professor  Stout  that  "  smells  are 
not  adapted  to  ideal  revival  in  serial  succession  as 
sounds  and  sights  are,"  and  therefore  do  not  figure 
in  those  trains  of  ideas  which  bulk  so  largely  in  our 
mental  life,  it  is  not  true  to  our  personal  experience 
to  say  that  man  has  no  olfactory  memory.  Civiliza- 
tion has  staked  so  much  on  eye  and  ear,  that  man's 
sense  of  smell  seems  to  be  on  the  down  grade.  But 
one  hopes  that  this  is  still  rather  individual  than 
racial,  that  is,  rather  modificational  than  variational, 
and  that  the  growing  love  for  gardens,  for  instance, 
may  do  something  to  counteract  the  exhaustion 
of  the  sense  by  tobacco  and  petrol.  One  of  the 
hints  that  we  get  from  Nature  is  that  a  fundamental 
secret  of  progressive  evolution  lies  in  a  broadening 
and  deepening  appropriation  of  the  complex  system 


102  SECRETS  OF  ANIMAL  LIFE 

which  has  been  wrought  out  through  the  ages 
around  the  organism,  and  admitting  a  small  minority 
of  stink-horns,  hounds'  tongues,  and  corn-spurreys, 
we  would  hold  firm  by  our  appreciation  of  that 
generously  widespread  frankincense  and  myrrh 
which  make  part  of  the  charm  of  the  summer  days. 


XIV 
COUNTRY  SOUNDS 

MAN'S  resting  instinct  is  not  strongly  devel- 
oped,  and  even  those  who  are  not  tethered 
to  toil  are  apt  to  go  on  working  far  too  long.  The 
stimulus  of  psychological  motives  is  often  strong 
enough  to  make  us  disregard  biological  warnings, 
and  there  are  familiar  devices,  such  as  a  pipe, 
by  which  fatigue  signals  can  be  muffled.  But 
one  of  the  well-known  symptoms  of  approaching 
the  danger-zone  of  fatigue  is  a  hyper-sensitiveness 
to  sounds,  especially  noises,  to  which  unfagged 
brains  with  plenty  of  energy  to  spare  are  quite 
indifferent.  Cases  have  been  recorded  of  the  jaded 
hearing  the  ringing  of  the  door-bell  in  a  house  many 
yards  off,  and  when  ordinary  urban  sounds 
begin  to  be  an  unusual  source  of  irritation  it  is  a 
hint  to  those  who  can  that  they  should  seek  the 
country.  For  it  is  beyond  doubt  that  part  of  a 
country  holiday  is  in  the  rest  to  the  ears.  The 
great  hush  that  wraps  the  hills  is  more  refreshing 
than  sleep. 

They  say  that  the  noisiest  thing  in  the  world 
is  a  sun-spot,  a  roaring  whirlpool  of  gases  in  the 
sun's  atmosphere  sometimes  thousands  of  miles  in 
Diameter;  but  of  the  whirlpool  which  Huxley 

103 


104          SECRETS  OF  ANIMAL  LIFE 

discerned  in  every  organism  we  usually  hear  no 
sound.  Matter  and  energy  are  continually  passing 
in  and  passing  out — a  turmoil  of  molecules,  yet  all 
to  us  seems  quietness !  There  are  combustions  and 
explosions,  solutions  and  hydrations,  reductions 
and  fermentations;  the  living  body,  Sir  Michael 
Foster  used  to  say,  is  "  a  vortex  of  chemical  and 
molecular  change  " ;  and  yet  our  ears  hear  nothing 
of  the  bustle.  In  all  these  growing  creatures  round 
about  us  in  the  woods  and  meadows  there  is  in  every 
dividing  cell  an  extraordinary  manceuvering  and 
meticulous  splitting  of  muclear  rods,  yet  all  is 
quieter  than  a  dumb-show.  Walt  Whitman  has 
spoken,  we  think,  of  the  bustle  of  growing  wheat, 
but  the  striking  feature  about  vital  processes  is  their 
silence.  How  quietly  are  the  houses  broken  down 
and  built  up  again  in  the  streets  of  the  living  body; 
how  silently,  like  ghosts,  do  the  molecules  of  these 
colloid  crowds  rush  past  one  another!  Lucky, 
indeed,  this  is  for  us;  in  the  midst  of  the  crowded 
life  of  the  country  we  enjoy  quietness,  and  one 
panting  locomotive  in  the  distance  makes  more 
to-do  than  all  the  millions  of  animals  and  plants, 
except  in  the  season  of  the  singing  of  birds  (some 
golfers  complain  of  the  larks  on  the  links  putting 
them  off  their  game),  and  on  such  unusual,  rather 
artificial,  occasions  as  the  separation  of  the  lambs 
from  their  mothers.  Then  the  whole  night  is  full 
of  clamor. 

In  temperate   countries,   where  violent  changes 
are  rare,  most  of  the  sounds  of  the  inorganic  world 


COUNTRY  SOUNDS  105 

are  subdued.  There  is,  indeed,  the  roll  of  the 
thunder,  the  battery  of  the  angry  sea,  the  howling 
of  the  storm,  the  ominous  crash  of  avalanche  and 
landslip,  the  roar  and  cannonading  of  the  forest 
fire,  the  groaning  and  travailing  of  the  earthquake, 
and  the  booming  of  the  cataract,  but  all  these  are 
more  or  less  unusual.  What  we  are  more  accus- 
tomed to,  what  we  have  come  to  love,  are  gentler, 
subtler  sounds  with  some  music  in  them  * — the  sob 
of  the  sea,  the  sough  of  the  wind  in  the  wood,  the 
song  of  the  purling  brook,  the  crickle-crackle  of  the 
brittle,  withered  grass  and  shriveling  herbage, 
the  sigh  with  which  the  parched  ground  receives 
the  heavy  rain,  and  the  little  sound  that  the  breeze 
evokes  when  it  rings  the  sun-dried  bluebells  by  the 
wayside,  or  makes  the  aspen  leaves  quiver,  or  sets 
the  heather  tinkling,  or  gives  a  whisper  of  gossip 
to  the  bulrushes  beside  the  lake. 

It  always  seems  worthy  of  remembrance  that  for 
many  millions  of  years  inorganic  sounds  were 
the  only  sounds  upon  the  earth,  for  it  was  not  until 
living  creatures  had  been  cradled  and  fostered  for 
many  seons  that  they  found  voice.  Insects  were 
the  first  to  break  the  silence,  and,  as  is  well  known, 
their  sound-production  is  almost  wholly  instrumen- 
tal. Buzzing  or  humming  is  mainly  due  to  rapid 
vibrations  of  the  wings,  which  often  strike  the  air 
more  than  a  hundred  times  in  a  second,  but  there  is 
sometimes  a  special  quivering  instrument  near  the 

1  This  article  was  published  before  Sir  Francis   Darwin's 
book  entitled  Rural  Sounds  (1917). 


106          SECRETS  OF  ANIMAL  LIFE 

base  of  the  wing.  Chirping  or  trilling  is  due  to  some 
sort  of  "  stridulating  "  organ,  one  hard  part  being 
scraped  against  another,  as  the  bow  on  the  fiddle — 
it  may  be  leg  against  wing,  or  limb  against  body. 
A  true  voice,  due  to  the  vibration  of  vocal  cords 
as  the  air  from  the  windpipe  passes  over  them, 
began  in  the  amphibians,  but  did  not  come  to  its 
own  till  birds  and  mammals  appeared  on  the  scene. 

As  the  inorganic  sounds  of  Temperate  zones  are, 
on  the  whole,  less  violent  than  those  of  the  Tropics, 
so  is  it  also  with  the  sounds  made  by  our  animals. 
They  may  be  included  in  the  reproach  implied  in 
Heine's  definition  of  silence  as  the  conversation  of 
an  Englishman.  How  little  we  have  that  can  be 
compared  with  the  serenading  of  the  tree-frogs,  the 
orchestra  of  grasshoppers  and  Cicadas,  the  chatter 
of  parrots  and  monkeys  in  warmer  countries! 
Except  during  the  time  of  bird-courtship  our  coun- 
try is  certainly  very  quiet.  We  visited  the  other 
day  an  apiary  with  about  a  hundred  hives;  the 
air  was  thick  with  bees,  and  their  coming  and  going 
along  the  broad  glass-covered  tunnel  of  an  observa- 
tion hive  was  like  the  Strand  at  a  crowded  hour. 
There  were  hundreds  of  thousands  of  bees,  and 
though  the  hum  was  stronger  than  we  ever  heard 
before,  even  in  an  avenue  of  lime-trees  in  flower, 
it  merely  filled  the  air  with  a  pleasant,  tremulous 
bourdon  of  sound. 

We  went  in  the  August  gloaming  to  a  beautiful 
lake  hidden  in  a  forest  of  Scots  pine  and  spruce. 
As  far  as  one  could  see  there  were  only  two  birds 


COUNTRY  SOUNDS  107 

visible,  a  pair  of  dabchicks,  diving  every  minute  or 
two,  and  uttering  now  and  then  the  gentlest  possible 
whit-whit  which  one  would  not  have  heard  if  the 
hush  had  not  been  almost  inviolate.  Now  and 
again  a  silvery  trout  leaped  high,  suggesting  Ex- 
calibur;  but  that  was  all — till  suddenly  a  ring-dove 
gave  voice,  with  its  deep,  rich  coo-roo,  wonderfully 
soothing  and  tender.  (One  must  not  allow  agri- 
cultural interests  to  obtrude  on  such  occasions.) 
Not  far  off,  some  one,  we  know  not  why,  had  set  fire 
to  a  giant  ant-hill,  which  was  flaming  on  the  top 
and  glowing  deep  red  in  its  recesses.  But  from 
the  conflagration,  with  its  tens  of  thousands  of 
victims,  and  from  the  melee  hurrying  from  the 
burning  city  there  came  no  sound  at  all.  It  is  not 
so  much  that  the  country  is  sparsely  peopled  with 
animals — a  fallacious  impression  due  to  the  "  crypto- 
zoic  "  habits  of  the  great  majority — it  is  simply 
that  relatively  few  animals  act  rapidly  on  matter, 
for  that  is  the  cause  of  sounds  like  the  wood- 
pecker's hammering,  or  the  snipe's  drumming; 
and  that  most  of  our  animals  have  soft  voices,  or 
have  not  very  much  to  say. 

Just  as  people  vary  considerably  in  acuteness  of 
vision,  so  some  hear  many  sounds  which  escape 
others.  Thus  a  keen-eared  correspondent  tells  me 
that  he  hears  the  stroke  of  a  bat's  wing  and  the 
closing  of  its  jaws  on  an  insect,  the  munching  of  a 
caterpillar,  and  the  rustle  of  an  earthworm. 

In  midsummer  in  the  North  of  Scotland  there  is 
hardly  any  darkness  at  all — one  can  sometimes  see 


108  SECRETS  OF  ANIMAL  LIFE 

to  read  at  midnight,  and  there  are  not  more  than  two 
hours  when  the  larks  at  least  are  not  singing.  The 
days  are  now  shortening  quickly  and  the  silent  hours 
must  be  longer,  yet  in  the  very  dead  of  night  we 
hear  the  dwellers  in  darkness  on  the  hunt.  There 
is  the  hedgehog,  for  instance,  which  calls  incisively 
in  the  stillness  with  a  peculiar  voice  between  grunt 
and  squeal.  Even  in  Aberdeenshire  the  whir  of 
the  nightjar  is  sometimes  heard  and  the  loud  clap 
of  its  wings  together,  as  it  hawks  for  nocturnal 
insects,  or  the  vibrating  "  churr  "  of  the  male  seated 
lengthwise  on  a  branch.  The  shriek  of  the  barn- 
owl  and  the  tu-whit,  tu-who  of  the  tawny  owl  are 
familiar  night  sounds,  and  some  people  can  hear 
the  voice  of  bats.  Soon  after  cock-crow  one  is 
wakened  by  the  rather  startling,  raucous  bark  of 
certain  black-headed  gulls  who  come  to  see  whether 
there  are  any  fragments  left  where  the  hens  are 
fed,  and  they  are  soon  followed  by  the  more  cheerful 
jackdaws.  Then,  on  the  adjacent  moor,  the  cock 
grouse  welcomes  the  sun;  swifts  then  begin  their 
chase — they  will  be  soon  leaving  us — and  their 
half-triumphant,  half -delirious  cry,  in  bad  weather 
and  in  good,  is  the  last  thing  we  hear  at  night. 

Particular  places  have  their  characteristic  sounds, 
which  we  listen  for  expectantly.  The  moorland 
would  be  incomplete  without  the  melancholy  cry 
of  the  curlew7,  with  a  melodious  ripple  at  the  nesting- 
time;  in  the  bed  of  the  stream  we  wait  for  the 
oyster-catcher's  alarm- whistle  keep-keep;  by  the 
estuary  we  enjoy  the  redshank's  warning  call  with  a 


COUNTRY  SOUNDS  109 

pleasant  trill  in  it,  which  the  male  raises  to  a  higher 
power  in  spring;  among  the  furze-bushes  beside 
the  dry  wall  the  stonechats  seem  to  "chap"  the 
stones  together;  the  peewits  cry  plaintively  from 
the  farmer's  fields;  as  we  take  a  short  cut  across 
the  heathery  "preserve,"  grouse  after  grouse  pro- 
claims our  trespass  with  a  ridiculously  silly  cachin- 
nation  kok-kok-kok;  but  best  of  all  we  like  "the 
moan  of  doves  from  immemorial  elms." 

It  is  only  in  manuals  of  psychology  that  we  get 
pure  sensations  and  pigeon-holed  perceptions,  for 
around  all  the  country-sounds  that  have  become 
dear  to  us  there  have  gathered  memories,  associa- 
tions, ideas,  and  we  hear  with  more  than  the  hearing 
of  the  ear.  There  are  wonderful  "  wireless  "  mes- 
sages which  the  imagination  can  catch.  As  we  walk 
at  nightfall  across  the  common,  noiselessly  we  think, 
a  dog  barks  just  once  or  twice  from  a  cottage  door 
half  a  mile  away,  and  then,  before  the  utter  quietness 
is  resumed,  we  hear  the  children  turn  in  bed,  the 
click-clack  of  their  mother's  knitting-needles,  the 
rustle  of  the  newspaper  which  the  shepherd  is  read- 
ing by  the  fireside ;  and  we  see  back  into  prehistoric 
times  when  man,  whose  life  depended  on  recogniz- 
ing and  interpreting  sounds,  began  to  evolve  the  first 
cousin  of  a  wolf  into  the  trusty  guardian  of  his  herds 
and  hearth.  So  is  it  with  the  other  familiar  country 
sounds;  we  hear  not  them  alone,  but  what  they  are 
symbols  and  sympathetic  echoes  of;  for  man  is 
ever  reading1  himself  into  the  so-called  outer  world. 
It  is  his  particular  magic  to  hear  in  the  lark's 


110  SECRETS  OF  ANIMAL  LIFE 

miracle  of  song  the  music  of  Shelley  and  the 
wisdom  of  Meredith,  to  infer  the  cherubim  from 
the  chaffinch,  and  to  find  in  the  "  lily-muffled  hum 
of  a  summer-bee,  some  coupling  with  the  spinning 


XV 

THE  FALL  OF  THE  YEAR 

THE  fine  days  of  autumn  are  rich  in  quiet 
delight.  They  salve  our  minds  through  our 
senses,  and  we  feel  the  healing  power  of  Nature. 
The  suggestion  of  frost  in  the  air  gives  a  spice  to 
exercise  and  braces  the  body.  From  the  fallen 
leaves  and  rustling  brittle  herbage  there  rises  a 
pleasant  smell,  sometimes  antiseptic,  sometimes  like 
that  of  ripe  apples.  Every  day  the  woods  have  a 
deeper  flush  as  the  leaves  slowly  wither,  and  we  saw 
a  wild  cherry  tree  on  the  edge  of  the  hill  which 
burst  into  flame  when  the  sunlight  struck  its  red 
leaves — a  "  burning  bush,"  and  no  mistake.  The 
children  are  gathering  "brambles,"  their  brightly- 
colored  scarfs  and  jackets,  their  red  cheeks,  their 
stained  lips  in  pleasant  tone  with  the  ripe  and 
ripening  berries  and  with  the  withering  leaves  as 
resplendent  as  those  of  the  vine.  Some  bigger 
boys  and  girls  who  had  been  working  all  Saturday 
in  the  potato  field  were  set  free  at  five  o'clock,  and 
it  was  a  pleasant  sight  when  they  came  bounding 
over  the  fence  into  the  road  with  an  alacrity  to 
which  the  prospect  of  supper  doubtless  prompted. 

Compared  with  spring  and  early  summer,  autumn 
is,  of  course,  a  very  quiet  time  in  the  country; 

111 


112  SECRETS  OF  ANIMAL  LIFE 

for  most  of  the  singing  birds  have  gone,  and 
the  instrumental  music  of  crickets,  grasshoppers, 
and  similar  phonating  insects  has  stopped  for  the 
season.  Just  as  we  were  thinking  of  this,  however, 
we  heard  curlews  calling  to  one  another  encourag- 
ingly as  they  flew  from  the  moorland  towards 
their  winter  quarters  by  the  seashore.  There  are 
also  rooks  and  gulls,  larks  and  robins,  and  a  few 
other  birds  to  be  heard.  Large  numbers  of  lap- 
wings have  been  very  busy  lately  hunting  small 
deer  in  the  bare  fields,  and  some  are  speaking 
in  a  subdued  way  to  one  another  as  they  unite  into 
bands  to  migrate  from  Aberdeenshire  to  Ireland — 
one  of  their  favorite  autumnal  journeys.  At  the 
same  time  it  must  be  admitted  that  autumn  is  not 
very  vocal,  and  we  have  to  put  the  gain  in  color 
against  the  loss  in  sound.  The  rather  overwhelming 
greenness  of  the  vegetative  period  has  been  replaced 
by  a  great  variety  of  hue,  as  when  white  light  is 
split  up  by  a  prism,  and  though  the  splendor  of 
individual  flowers  has  passed,  there  are  big  splashes 
of  color  that  offer  compensation. 

So  much  for  sensory  delight,  but  there  is  also  a 
wealth  of  scientific  interest.  The  great  wave  of  life 
gathers  strength  in  spring,  rises  to  its  full  height  in 
summer,  sinks  to  rest  in  winter;  the  breaking  time 
is  autumn,  and  no  season  is  richer  in  problems. 
We  stoop  and  look  along  the  links  towards  the 
sinking  sun,  and  we  see  the  quivering  of  myriads 
of  fallen  gossamer  threads  which  earlier  in  the  day 
served  multitudes  of  small  spiders  as  silken  para- 


i.       THE  FALL  OF  THE  YEAR  113 

chutes.  From  a  crowded  area  the  little  spinners 
were  borne  in  passive  migration  on  the  wings  of 
the  wind,  and  the  tangle  of  gossamer  on  the  grass 
tells  of  the  accomplished  journeys.  In  the  forenoon 
the  threads  glisten  with  dew  or  thawed  hoar-frost, 
making  one  of  the  finest  sights  in  the  world — 
"  every  thread  of  cobweb  dew-bediamonded,"  as 
R.  L.  Stevenson  put  it — and  all  the  finer  in  our 
eyes  because  we  know  that  the  gossamer  strewn  in 
disarray  spells  a  victory  of  life  over  matter. 
Showers  of  gossamer  are  not  by  any  means  re- 
stricted to  autumn,  but  they  are  in  many  localities 
very  characteristic  of  that  season,  and  we  may  link 
them  in  thought  to  the  more  active  migrations  of 
birds — migrations  which  have  taken  from  us  all  our 
summer  visitors  and  are  bringing  us  a  small  con- 
tingent of  winter  visitors,  such  as  fieldfares  and 
redwings,  snow  buntings  and  great  northern  divers. 
There  are  also  incoming  flocks  of  various  sorts 
(gold-crests  and  hoodie-crows  make  a  good 
contrast)  which  take  Great  Britain  en  route  as  they 
wend  their  way  from  Scandinavia  to  the  genial 
South. 

Another  very  characteristic  sight  in  autumn  is 
the  rush  of  the  salmon  up  the  rapids  and  over  the 
falls  on  their  way  to  the  spawning-grounds  where 
the  females  deposit  their  eggs  in  the  gravel — usually 
in  November  and  December  in  Scotland.  Their 
nutritive  period  in  the  sea  has  given  them  great 
stores  of  energy  for  their  fasting  but  reproductive 
period  in  the  rivers;  they  are  influenced,  no  doubt, 


SECRETS  OF  ANIMAL  LIFE 

by  the  temperature  and  oxygenation  of  the  water 
and  so  on;  they  are  impelled  by  an  internal  spur — 
a  seasonal  change  of  constituti6n;  but  in  thinking 
over  this  return  to  their  natal  waters,  or  to  waters 
similar  in  character,  we  probably  go  far  wrong  in 
the  direction  of  false  simplicity  if  we  do  not  recog- 
nize in  the  salmon  struggling  against  the  stream  a 
bent  bow  that  is  more  than  material.  We  mean  that 
in  its  way  the  salmon  is  a  personality — a  piscine 
personality  if  you  will — with  a  life  not  only  of 
contracting  and  relaxing,  digestion  and  combustion, 
and  so  on,  but  a  life  of  feeling  and  willing  besides, 
the  two  making  one.  And  just  as  the  salmon 
illustrates  an  intensely  active  genetic  impulse,  the 
expression  of  physiological  and  psychical  enregistra- 
tions  both  racial  and  personal,  so  in  these  wind- 
borne  clouds  of  winged  fruits  and  parachuted  seeds 
we  see  on  a  very  different  level  and  with  little  hint 
of  "  the  bent  bow  "  the  same  fascinating  problem 
of  adaptations  which  secure  the  continuance  of  the 
race  from  generation  to  generation. 

The  familiar  withering  and  fall  of  the  leaves 
can  never  fail  to  excite  the  interest  of  those  who 
keep  alive  the  curious  spirit.  What  busy  synthetic 
laboratories  they  have  been  all  the  summer  through, 
what  abundance  of  complex  carbon  compounds 
have  they  manufactured!  and  now  the  laboratory 
furnishings  are  worn  out  and  the  leaves  must  die. 
But  there  is  high  art  in  their  dying;  for  there  is  a 
migration  of  almost  all  that  is  valuable  from  leaf  to 
stem,  so  that  little  more  than  waste  is  left  to  fall; 


THE  FALL  OF  THE  YEAR  115 

there  is  the  fine  surgery  which  cuts  the  link  between 
dying  and  living  and  at  the  same  time  bandages 
the  wound  (recalling  quaintly  enough  the  throwing- 
off  of  a  leg  in  crab  and  lobster) ;  and  there  is 
the  "beauty  for  ashes"  due  to  the  breaking  up 
of  the  chlorophyll  and  the  formation  of  special 
decomposition  pigments  like  anthocyan.  And, 
looking  ahead,  we  see  the  earthworms  dragging 
the  fallen  leaves  into  their  burrows,  and  thereby 
making  vegetable  mold  in  which  they  sometimes, 
all  unconsciously,  plant  the  seeds  of  future 
trees.  We  wonder  whether  there  is  in  animate 
Nature  any  more  beautiful  sequence  of  adaptive 
events. 

The  wasps'  nest,  a  model  of  "  efficiency  "  in  the 
summer-time,  is  falling  into  ruins;  all  the  tenants 
have  gone,  and  intruders  are  pillaging  the  edifice. 
The  ranks  of  the  workers  were  thinned  weeks  ago 
by  bad  weather  and  cold;  the  parent  queen  died 
of  exhaustion;  the  surviving  workers  ate  up  the 
remaining  grubs  and  died  also;  the  drones  likewise 
disappeared,  so  now  the  sole  survivors  of  the  colony 
are  the  young  queens,  who,  after  mating,  sought  out 
secluded  corners  where  they  have  fallen  into  their 
"  winter  sleep."  For  humble-bees  the  story  is  in  a 
general  way  the  same;  only  the  young  queens  are 
left,  hidden  in  their  winter  quarters.  Contrast  this, 
however,  with  hive-bees  under  man's  aegis.  The 
elaboration  of  the  storing  instincts,  the  greater 
division  of  labor  and  solidarity,  and  the  more 
permanent  "  hive  "  have  made  it  possible  for  the 


116          SECRETS  OF  ANIMAL  LIFE 

community  to  evade  the  terrific  autumnal  elimina- 
tion seen  in  ordinary  wasps  and  humble-bees.  The 
activities  in  the  hive  sink  to  a  minimum,  it  is  true, 
but  the  point  is  that  the  community  lasts,  and  in  a 
favorable  year  should  not,  after  yielding  much 
honey  to  their  owner,  require  any  winter  feeding 
from  him  if  he  is  not  too  greedy  in  what  he  exacts. 
But  every  one  knows  that  there  is  autumnal 
tragedy  in  the  beehive  too,  for  some  time  after 
the  queen  has  been  fertilized  the  workers  unite 
to  destroy  the  now  useless  drones,  either  murder- 
ing them  directly  or  driving  them  forth  to 
perish. 

Deeper  than  the  particular  problems  of  the  natural 
history  of  autumn  is  the  general  biological  problem 
of  what  it  all  means,  and  the  answer  is  that  the 
seasons  are  externally  instituted  periodicities  to 
which  organisms  have  had  to  adapt  themselves. 
But  it  is  not  merely  that  living  creatures  have  be- 
come in  a  self-preservative  way  fitted  to  cope  with 
or  circumvent  the  difficulties  of  the  seasons;  they 
have  also  evolved  subtle  tactics  which  have  made 
use  of  the  difficulties  as  opportunities  for  advance. 
Just  as  the  alternation  of  hard  work  and  quiet  rest, 
physiologically  natural  in  higher  animals,  fits  in  well 
with  the  alternation  of  day  and  night,  so  rhythms 
of  longer  period  fit  in  well  with  the  periodicities  of 
the  seasons.  It  cannot  be  said  that  the  alterna- 
tion of  work  and  rest,  including,  for  instance,  the 
"  loading  "  and  "  unloading  "  of  internal  glands,  is 
the  direct  and  necessary  result  of  the  alternation  of 


THE  FALL  OF  THE  YEAR  117 

day  and  night,  for  some  creatures,  such  as  hive-bees, 
work  all  night  as  well  as  all  day;  and  similarly  it 
cannot  be  said  that  the  periodicities  of  the  seasons 
are  the  direct  causes,  say,  of  the  winter  blanching 
of  the  mountain  hare  and  the  ptarmigan,  or  of  the 
hibernation  of  hedgehog  and  bat,  or  of  the  migra- 
tion of  most  North  Temperate  birds.  All  that  we 
can  say  is  that  external  periodicities  and  internal 
rhythms  have  interacted  for  ages  so  that  an  adaptive 
adjustment  has  been  arrived  at. 

What  do  we  see,  then,  in  the  tactics  of  autumn? 
In  the  first  place,  there  is  a  great  variety  of  arrange- 
ments for  the  continuance  of  the  race  even  when 
the  individual  lives  come  to  an  end.  This  is 
illustrated  by  the  autumn  fruits  and  by  the  prodigal 
seed-scattering,  by  the  salmon  rowing  hard  against 
the  stream,  by  the  queen  wasps  and  queen  humble- 
bees  seeking  out  winter  quarters,  by  the  honey-bees 
snuggling  together  in  the  hive.  In  the  second  place, 
there  is  a  sacrifice  of  parts  which  saves  the  whole, 
as  when  the  leaves  fall  from  the  trees  which  they 
have  enriched,  or  when  the  hive-bees  massacre  the 
drones,  or  when  there  is  terribly  drastic  reduction 
of  numbers  among  wasps  and  humble-bees.  In  the 
third  place,  there  is  preparation  for  hard  times  to 
come,  as  is  illustrated  in  the  automatic  vegetative 
storing  of  starch  and  the  other  reserve  products  by 
plants,  in  the  instinctive  storing  of  honey  by  hive- 
bees  and  of  grain  by  ants,  and  in  the  half-instinctive 
and  half -intelligent  storing  of  nuts  by  squirrels  and 
of  earthworms  by  moles.  There  is  the  making  or 


118  SECRETS  OF  ANIMAL  LIFE 

collecting  of  blankets  against  the  winter's  cold,  as 
is  illustrated  by  the  non-conducting  scales  around 
the  buds,  by  the  sleeping-sacks  which  caterpillars 
fashion  before  sinking  into  their  chrysalid  lethargy, 
by  the  soft  quilts  gathered  into  their  winter  resting- 
places  by  dormice  and  other  true  hibernators.  The 
blanching  of  mountain  hare  and  ptarmigan  is  also  a 
protective  preparation.  In  the  fourth  place,  there 
is  what  one  may  dare  to  call  the  circumvention  of 
difficulties.  The  clearest  illustration  is  in  the 
migration  of  the  majority  of  North  Temperate  birds 
to  comfortable  winter  quarters  in  the  South.  They 
evade  impending  disasters  so  triumphantly  that 
they  know  no  winter  in  their  year.  Or,  again,  in 
true  hibernation  of  hedgehog  and  bat,  dormouse 
and  marmot,  there  is  a  relapse  from  the  normal 
"  warm-bloodedness,"  a  seasonal  sinking  back  to- 
ward an  ancestral  "  cold-bloodedness,"  which  leaves 
the  creature  less  open  to  the  assaults  of  the  winter; 
able,  indeed,  to  defy  them,  especially  within  a 
secluded,  confined,  and  often  well-blanketed  sleeping 
chamber.  Even  in  the  lethargy  of  tortoise  and  frog, 
snail  and  chrysalid,  which  must  not  be  mixed  up 
with  true  hibernation  (confined  to  a  few  mammals), 
there  is  the  same  general  idea  of  relapse  into  a 
condition  of  "  lying  low  "  physiologically,  which 
renders  the  creature  much  less  open  to  attack.  The 
fire  of  life,  well  banked  up,  almost  smothered  in  its 
own  ashes,  burns  very  low  through  the  night  of 
winter,  and  "keeps  in."  No  doubt  the  fall  of  the 
year  means  retrenchment  and  sacrifice,  retreat  and 


THE  FALL  OF  THE  YEAR  119 

sifting;  but  those  who  study  the  biology  of 
autumn  attentively  will  recognize  much  more — a 
multitude  of  adaptations,  automatic,  instinctive, 
and  intelligent,  which  secure  continuance,  persist- 
ence, victory. 


XVI 
THE  SURVIVAL  OF  THE  OTTER 

THE  otter  is  so  shy  a  creature  that  few  British 
naturalists  have  had  more  than  tantalizing 
glimpses  of  its  everyday  (or  rather,  everynight) 
life,  wherewith  to  supplement  what  they  know  of 
the  animal  in  zoological  gardens,  and  what  they 
have  gathered  from  a  study  of  its  structure — the 
finely-molded  skull,  for  instance.  This  gap  in  our 
knowledge  was  filled  a  few  years  ago  by  Mr.  J.  C. 
Tregarthen's  Life  Story  of  the  Otter?-  The  author's 
observational  patience  arid  sympathy,  shown  also 
in  his  biographies  of  fox  and  hare,  have  enabled 
him  to  disclose  the  vie  intime  of  an  animal  which  is, 
to  say  the  least,  very  unapproachable.  We  hope 
that  our  appreciation,  at  once  of  the  beast  and  the 
book,  will  serve  to  introduce  Mr.  Tregarthen's 
delightful  studies  in  Natural  History  to  some  who 
have  not  had  the  pleasure  of  knowing  them.  The 
question  with  which  we  are  especially  concerned  is 
how  the  otter  manages  to  hold  its  own  in  Britain, 
where  so  many  of  its  Order,  such  as  badger  and 
wild  cat,  polecat  and  marten,  have  become  very 
few  and  far  between.  It  is  not  enough  to  refer  to 
the  otter's  cerebral  endowments,  its  keen  senses  of 

1  Murray,  London,  1915. 
120 


THE  SURVIVAL  OF  THE  OTTER   121 

sight,  hearing,  touch,  and  smell,  its  muscular  equip- 
ment, so  marked  in  the  grip  of  its  jaw,  the  back- 
stroke of  the  hind-legs,  and  the  sweep  of  the  steering 
tail,  for  the  mammals  we  mentioned  above  are  not 
deficient  in  these  qualities,  and  yet  they  have 
nowadays  a  tenure  of  life  much  less  secure  than 
the  otter's. 

What  particular  virtues  has  the  otter  that  enable 
it  to  keep  its  foothold  in  spite  of  man's  persecution 
and  the  reduction  of  natural  preserves?  The 
general  answer  is  probably  that  the  otter  has  rela- 
tively few  wild  enemies,  and  that  it  is  one  of  the 
most  elusive  of  beasts,  in  great  part  nocturnal  in 
its  activities,  shy  of  repeating  itself,  shifty  in  its 
hunting,  and  very  thoroughly  amphibious.  Mr. 
Tregarthen  calls  attention  also  to  the  faintness  of 
the  otter's  scent,  "  noticed  by  few  dogs  save  hounds 
that  have  been  trained  to  own  it,"  and  to  its  re- 
sourcefulness and  endurance  when  hunted.  Part  of 
the  secret  of  survival  must  also  lie  in  the  catholicity 
of  appetite,  for  while  the  otter  depends  in  the  main 
on  eels,  trout,  salmon,  pike,  flatfish,  and  the  like,  it 
condescends  to  the  mussels  on  the  seashore  (biting 
through  their  shells),  the  limpets  on  the  rocks,  and 
the  frogs  on  the  marsh,  and  rises  to  wild-duck  and 
rabbit.  It  must  also  be  remembered,  as  in  regard 
to  fox-hunting,  that  whatever  be  our  humanitarian 
or  artistic  views  in  regard  to  the  otter-hunt,  the 
probability  is  that  sportsmen,  who  leave  the  cubs 
unmolested,  make  for  the  otter's  survival  rather 
than  for  its  disappearance.  The  aegis  of  sport 


122          SECRETS  OF  ANIMAL  LIFE 

has  saved  the  creature   from  being  exterminated 
for  the  sake  of  its  fur.1 

One  of  the  admirable  qualities  of  the  otter  is  the 
intensity  of  the  parental,  especially  the  maternal, 
care.  The  young  ones — blind  and  downy — are  born 
in  a  soft-lined  nest  under  the  shelter  of  an  inaccessi- 
ble bank;  the  mother  will  at  first  hardly  leave  them 
save  on  feverish  rushes  after  the  food  necessary 
to  keep  up  the  supply  of  milk.  To  guard  them  she 
sleeps,  like  many  a  human  mother,  with  at  least 
one  ear  awake.  When  they  open  their  eyes  she 
cautiously  carries  them  to  bask  for  a  while  in  the 
winter  sunshine,  for  their  birthdays  are  often  in 
January.  When  they  can  clamber  she  teaches 
them  the  woodcraft  of  the  immediate  vicinity  of 
the  "  hover "  and  the  complete  alphabet  of  the 
sounds  that  mean  danger.  With  her  teeth  she 
punishes  disobedient  foolhardiness — especially  on 
the  part  of  the  male  cubs — yet  she  shares  in  their 
frolics  when  all  sensible  danger  is  distant.  When 
they  are  a  little  over  eight  weeks  old  and  able  to 
follow  her  afield,  she  takes  them  to  a  quiet  pool  and 
teaches  them  to  swim,  supplying  by  a  gradual 
widening  of  experience  the  liberating  stimuli  that 
are  needed  to  arouse  their  instinctive  endowments, 
In  about  a  week  they  can  swim  with  the  fishes — a 
week  which  seems  more  like  play  than  school,  for  the 
otter  is  one  of  the  animals  in  which  there  is  pro- 

1  For  the  other  side  of  the  picture— a  sorry  one— see  Joseph 
Collinson's  Hunted  Otter.  Animals'  Friend  Society,  London, 
J9H, 


THE  SURVIVAL  OF  THE  OTTER  123 

longed  playfulness  in  youth — a  period  of  irre- 
sponsible and  apparently  joyous  apprenticeship  to  the 
future  business  of  life.  Who  shall  say  that  the 
mother  does  not  in  some  measure  renew  her  youth  as 
she  shares  in  the  "  hide-and-seek  "  and  gambols  of 
her  cubs?  It  is  indeed  a  remarkable  fact  in  regard 
to  this  fascinating  animal  that  playfulness  never 
quite  leaves  it;  that  even  the  fathers  and  mothers 
of  families  cannot  resist  the  appeal  of  situations 
that  suggest  a  frolic,  and  that  they  will  play  up 
to  the  very  gates  of  death — "most  playsomest 
critturs  on  God's  earth,"  said  one  of  Mr.  Tregar- 
then's  Cornish  friends. 

To  return  to  education,  the  young  cubs  have  also 
to  learn  to  like  the  taste  of  fish,  to  catch  them 
without  fuss,  and  to  eat  them  in  the  proper  way — 
the  eel  from  the  tail  and  the  trout  from  the  head. 
They  have  to  learn  how  to  catch  frogs  and  how 
to  skin  them,  for  the  outside  is  unpalatable;  how 
to  guddle  for  trout  and  eels;  how  to  detect  the 
plaice  in  the  shallow  waters  of  the  bay,  hidden  in 
or  against  the  sand,  with  only  their  eyes  showing. 
They  have  to  learn  how  to  deal  with  rabbit  and 
moorhen,  and,  through  it  all,  they  have  to  keep 
working  away  at  the  long  alphabet  of  danger- 
sounds — especially  those  proceeding  from  man  and 
dog.  They  have  to  learn  all  the  diverse  ways  of 
lying  perdu  in  and  out  of  the  water.  There  can  be 
no  doubt  that  the  prolonged  youth  and  the  elaborate 
parental  instruction  count  for  much  in  the  per- 
sistent survival  of  the  otter — a  kind  of  fact  still 


124  SECRETS  OF  ANIMAL  LIFE 

inadequately  appreciated  by  those  who  hold  to  a 
conception  of  the  struggle  for  existence  which  is  too 
literal  and  wooden  to  be  accurate. 

Another  attractive  feature  about  the  otter  is  its 
nomadism ;  it  has  the  roving  spirit.  "  The  home- 
less hunter/'  Mr.  Tregarthen  calls  it,  "  the  Bedouin 
of  the  wild."  "It  has  been  known  to  travel  fifteen 
miles  in  a  night,  and  not  infrequently  the  holts  where 
it  lies  up  during  the  day  are  ten  or  twelve  miles 
apart."  It  passes  from  tarn  to  stream,  from  river 
to  shore ;  it  swims  far  out  to  sea  and  reaches  isolated 
rocks;  it  wanders  along  the  cliffs  and  explores  the 
caves;  it  crosses  the  heather-covered  hills,  and  even 
the  mountain  passes,  sheltering  among  the  bracken 
or  in  the  heart  of  a  cairn;  it  neither  stores  nor 
hibernates,  but  is  always  on  the  move — a  gipsy 
among  carnivores. 

Resourceful  is  the  appropriate  word  for  an  otter. 
For  it  is  equally  at  home  on  land  and  in  water,  by 
night  and  by  day,  in  a  dry  burrow  or  on  a  shelf  under 
a  waterfall;  it  can  enter  the  water  without  a  splash, 
swim  near  the  surface  with  scarce  a  ripple;  it  can 
dive  in  a  spiral  full  fathoms  five,  and  lie  under  the 
bank  on  a  stream  for  hours  with  its  nostril  in  a  space 
between  water  and  earth.  It  knows  its  own  foot- 
steps in  the  thicket  and  will  not  retrace  them;  it 
never  goes  back  to  a  kill,  for  that  way  danger  lies; 
it  will  carry  a  water-trap  on  its  shoulders  and 
wrench  it  off  on  the  alder-roots;  it  will  dive  at 
the  flash  of  the  gun  and  elude  the  bullet;  it  is 
an  outlaw  of  unsurpassed  alertness  and  resource. 


THE  SURVIVAL  OF  THE  OTTER   125 

There  are  savage  rights  between  two  dog-otters  who 
desire  the  same  mate,  and  the  strength  of  the  parents 
is  often  severely  taxed  in  providing  for  the  young; 
but  the  main  struggle  for  existence  among  these 
sharp-toothed,  strong-jawed  beasts  of  prey  is  not 
in  any  intra-specific  competition,  but  in  circumvent- 
ing difficulties  and  in  securing  food. 

The  severest  of  tests  is  a  hard  and  prolonged  frost. 
At  first  it  gives  an  added  spice  to  life,  for  strings  of 
wild-fowl  arrive  and  the  ice  on  the  mere  is  a  rare 
playground.  It  is  possible  for  the  otter  to  hunt 
for  pike  beneath  the  ice,  for  eels  and  tench  buried 
deep  in  the  mud.  But  there  is  circumstantial 
evidence  of  terrible  experiences  when  the  breathing 
holes  in  the  ice  freeze  quickly  and  the  otter  is  apt 
to  be  imprisoned  below,  when  the  parents  are 
tied  down  by  cubs  too  heavy  to  carry  and  not 
strong  enough  to  travel,  when  the  wild- fowl  leave 
the  sealed  waters  for  the  shore,  when  the  snow 
threatens  to  smother  the  family.  It  is  only  in 
such  straits  that  the  otter,  in  desperation,  begins 
to  experiment  by  nights  with  the  farmer's  ducks. 
This  last  resource  is  very  restricted,  however,  and 
the  conditions  may  prove  too  severe,  the  mother  at 
last  succumbing  to  her  efforts  to  get  food  for  herself 
and  her  offspring.  "At  Mullion,  in  Mount's  Bay, 
one  bitterly  cold  December,  when  the  Poldhu 
stream  was  frozen  and  the  sea  too  rough  and  dis- 
colored for  the  otter  to  fish,  the  poor  creature 
in  her  extremity  crept  into  a  bungalow  in  the 
course  of  erection,  and  was  there  found  curled  up 


126          SECRETS  OP  ANIMAL  LIFE 

dead.'*  We  are  indebted  to  Mr.  Tregarthen  for 
enabling  us  to  combine  in  a  living  whole  sundry 
personal  glimpses  we  have  had  of  this  attractive 
but  inscrutable  creature's  life,  and  for  giving  us  in 
answer  to  our  question  regarding  its  survival  these 
hints,  that  in  addition  to  great  natural  gifts  the 
otter  has  the  advantage  of  a  most  solicitous  mother- 
ing, of  a  careful  education  resulting  in  a  resource- 
fulness that  can  hardly  be  baffled,  and  of  a  roving 
spirit  which  becomes  expressed  in  an  unrivaled 
elusiveness.  Britain  will  indeed  be  the  poorer  if 
man's  ruthlessness  prove  eventually  too  much  for  a 
fascinating  creature  whose  grip  has  held  for  so  long. 


XVII 
MIDWINTER 

THE  biological  signficance  of  a  season  is 
clearest  in  extreme  cases,  and  there  is  no 
obscurity  about  the  meaning  of  winter  on  the  slopes 
of  the  Cairngorms.  The  keen  edge  of  what  would 
have  been  but  a  breeze  on  a  summer  day  suggests 
the  reaping-hook  of  elirpination — both  discriminate 
and  indiscriminate — which  every  winter  implies. 
The  blankets  of  snow  make  us  think  of  sleep  and 
rest,  and  so  does  the  silence.  One  remembers  how 
many  months  Nansen  spent  in  the  Far  North  without 
hearing  the  voice  of  a  single  bird.  Even  the  curlews 
have  long  since  left  the  moorland  for  the  shore, 
there  are  almost  no  footprints  on  the  snow,  and  we 
have  the  feeling  of  being  intruders  into  an  azoic 
domain.  Of  course  it  is  not  so  bad  as  it  looks,  for 
now  and  then  we  literally  catch  the  eye  of  a  ptar- 
migan in  winter  dress,  so  subtly  camouflaged  among 
the  snow,  and  that  movement  of  a  something  with 
a  cloak  of  invisibility  was  the  rush  of  a  startled 
white  hare.  No  doubt  there  is  considerable  crypto- 
zoic  life  about  the  roots  of  the  heather  and  so  forth; 
in  Canada  the  ruffled  grouse  dives  into  the  soft 
snow-drifts  and  makes  a  short  tunnel;  but  the 
general  fact  is  that  most  of  the  living  creatures 

127 


128  SECRETS  OF  ANIMAL  LIFE 

which  were  here  a  few  months  ago  are  asleep,  or 
have  gone  on  a  journey,  or  have,  as  individuals, 
ceased  to  be. 

The  wintry  aspect  of  the  realm  of  organisms  must 
be  considered  from  within  and  from  without,  for 
life  is  rhythmic  and  is  punctuated  by  the  seasons. 
On  the  one  hand,  there  is  a  deep  reason  why  high- 
level  activity  cannot  be  for  long  continuous,  why 
it  must  be  interrupted  by  periods  of  rest.  It  is 
not  merely  that  the  living  engine  has  to  be  stoked; 
it  is  that  the  framework  requires  opportunity  to 
keep  passably  young.  It  is  continuity  that  kills. 
For  many  creatures  winter  is  the  time  when  processes 
of  rejuvenescence  get  a  chance  to  counteract  the 
encroachments  of  senescence.  How  useful,  often, 
for  the  overworked  brain  is  it  to  sleep  the  round  of 
the  clock.  The  hibernal  slumbers  of  hedgehog  and 
dormouse,  of  marmot  and  bat,  the  winter  coma  of 
tortoise  and  slow-worm,  the  lethargic  condition  of 
frogs  and  snails,  are  no  doubt  adaptive  reactions  to 
severe  external  conditions,  subtle  organic  illustra- 
tions of  Brer  Rabbit's  policy  of  "lying  low  and 
saying  nuffin";  but  our  point  is  that  the  quiescence 
of  winter  has  in  some  cases  a  more  internal  aspect, 
it  is  the  inevitable  pause  in  a  strenuous  life.  Quite 
extraordinary  in  some  humble,  but  intensely  active, 
animals  (Bryozoa,  for  instance)  is  the  way  in  which 
the  framework  can  be  periodically  taken  to  pieces 
and  built  up  again.  One  suspects  that  organic 
immortality  is  commoner  than  is  usually  supposed. 
And  the  recuperation  has  obviously  a  prospective 


MIDWINTER  129 

as  well  as  retrospective  reference;  it  is  the  crouch 
before  the  leap.  Many  an  organism  has  learned 
the  lesson,  se  reculer  pour  mieux  sauter.  The 
repose  of  winter  gives  us  the  rebound  of  spring. 

On  the  moor  a  few  hundred  feet  lower  down  there 
are  scattered  birch  trees  with  bare  limp  branches 
on  the  pendulous  tips  of  which  the  sun  has  hung 
diamonds;  what  a  story  they  have  to  tell  us  of 
the  precarious  tenure  of  peripheral  organs  (as  the 
birch  leaves  fell  the  grouse  molted  its  claws!);  of 
the  usefulness  of  surrendering  vulnerable  organs; 
of  the  economy  of  the  organism,  for  the  leaves  in 
their  withering  gave  back  to  the  tree  all  that  they 
had  that  was  worth  keeping;  and  of  the  prepara- 
tions made  many  months  ago  within  the  well- 
protected  buds  for  the  foliage  and  flowers  of  the 
distant  spring. 

From  the  external  aspect  the  big  fact  is  that  the 
rate  of  chemical  reactions  is  increased  by  rise  of 
temperature,  since  that  means  increase  in  the  rate 
of  molecular  movements.  It  is  true  that  what  is 
called  van  Hoff's  Law  of  the  effect  of  temperature 
on  chemical  reactions  does  not  seem  to  fit  very 
well  for  the  changes  that  go  on  in  living  creatures, 
probably  because  these  are  such  heterogeneous 
systems,  in  which  physical  and  chemical  processes 
become  intricately  mixed  up;  but  the  broad  fact 
is  that  the  effect  of  warmth  is  to  increase,  and  the 
effect  of  cold  to~  decrease,  the  rate  of  vital  activity 
or  metabolism.  Moreover,  in  spite  of  glacier-fleas 
and  small  creatures  from  hot  springs,  the  great 


130          SECRETS  OF  ANIMAL  LIFE 

majority  of  active  animals  are  going  concerns 
between  very  narrow  limits  of  temperature.  A 
little  too  hot,  or  a  little  too  cold,  and  the  wheels 
won't  go  round  any  more.  We  need  not  go  into 
the  question  of  the  effect  of  cold  on  the  synthesis  of 
proteins,  on  which  the  continuance  of  vigorous  life 
depends;  and  we  confess  our  inability  to  explain 
the  metabolism  of  deep-sea  fishes,  for  instance, 
which  live  and  thrive — at  what  pace  we  do  not 
know — in  the  eternal  winter  of  the  great  abysses 
where  the  temperature  remains,  year  in  year  out, 
about  the  freezing-point  of  fresh  water;  but  the 
average  statement  is  safe  that  winter  puts  a  brake 
on  vital  activity.  Should  the  brake  be  put  on  too 
suddenly  or  too  forcibly,  the  equipage  of  life  may 
be  capsized  and  broken,  and  all  the  king's  horses 
and  all  the  king's  men  will  not  be  able  to  put  it  to 
rights.  As  many  as  two  hundred  dead  birds  have 
been  gathered  in  one  stackyard  after  a  night  of 
severe  frost.  The  thermometer  fell  just  a  little  bit 
too  far — beyond  the  limit  of  a  bird's  viability. 

So  it  is  no  small  part  of  the  biology  of  winter 
to  inquire  into  the  diverse  ways  in  which  living 
creatures  have  learned  to  meet,  or  are  learning  to 
meet,  the  time  of  cold  and  scarcity.  The  finest 
solution  of  all  is  that  of  the  migratory  birds,  "in- 
telligent of  the  seasons/'  as  Milton  put  it,  who 
circumvent  the  winter  by  seeking  lands  that  keep 
the  sun.  Very  effective  is  that  long  result  of  time 
called  warm-bloodedness,  whereby  birds  and  mam- 
mals are  able,  up  to  a  certain  limit,  and  in  varied 


MIDWINTER  131 

degrees  of  perfection,  to  adjust  the  internal  produc- 
tion of  heat  to  the  external  loss  of  it,  and  thus  keep 
an  approximately  constant  body-temperature  all  the 
year  round.  In  some  mammals  in  which  this 
"  thermotaxis "  arrangement  is  less  perfect  than 
usual,  there  is  a  breakdown  when  the  cold  comes 
on.  The  creature  gives  up  the  contest  and  sinks 
into  deep  slumber  in  some  confined  space,  to  the 
temperature  of  which  that  of  the  sleeper  approxi- 
mates. If  the  external  temperature  does  not  fall  too 
far,  this  hibernation  may  be  life-saving.  Similar, 
but  less  effective,  is  the  lethargy  of  cold-blooded 
animals  like  tortoises  and  frogs,  the  vital  collapse 
of  snails  and  chrysalids,  and  the  inactivity  of  many 
humble  creatures  in  sheltered  nooks  and  crannies. 
They  evade  the  winter  by  their  extreme  passivity; 
they  cannot  carry  on,  but  they  do  not  die. 

We  are  led  to  think  of  stores,  whether  inside  the 
body  in  the  form  of  fat  which  may  be  slowly  burnt 
away  in  winter  months,  or  outside  the  body  in  the 
form  of  nut-pits,  seed-granaries,  meat-larders,  and 
what  not.  The  climax  on  the  instinctive  tack  of 
evolution  is  to  be  found  in  the  societary  stores  made 
by  ants -and  bees.  Of  another  solution  we  are 
reminded  by  the  ptarmigan  and  the  hare  that  we 
startled,  good  examples  of  creatures  that  turn 
pale  under  the  spell  of  winter  till  they  are  white 
as  the  snow  itself.  The  white  cloak  may  help  in 
concealment  and  in  the  chase;  it  also  furnishes  the 
physiologically  most  comfortable  dress  for  a  warm- 
blooded animal  in  very  cold  surroundings.  We 


132  SECRETS  OF  ANIMAL  LIFE 

must  not  go  farther;  our  point  is  merely  to  suggest 
an  interesting  inquiry  into  the  great  variety  of 
ways  in  which  different  animals  solve  the  same 
problem  of  surviving  the  winter.  For  those  that 
have  no  solution  to  offer,  and  for  those  that  fumble 
with  their  solution,  winter  spells  sooner  or  later 
elimination. 

As  we  come  home  we  pass  a  little  tarn,  which  was 
such  a  merry,  busy  place  at  midsummer,  but  is  now 
half-frozen,  and  looks  as  lifeless  as  the  moor.  The 
water  round  the  edges  is  clear  and  clean,  but  peering 
down  we  cannot  see  the  slightest  stir  of  life.  Now 
the  biochemists  of  the  ponds  have  told  us  a  very 
interesting  thing:  that  the  dying  away  in  autumn 
and  winter  produces  substances  ("auxetics") 
which  later  on  promote  the  multiplication  of  cells 
and  towards  spring  an  increasing  quantity  of  certain 
other  substances  ("augmentors")  which  give  more 
power  to  the  elbow  of  the  first.  And  so  out  of  death 
come  the  stimulants  of  the  wonderful  awakening 
of  pond-life  in  spring.  There  is,  no  doubt,  in  that 
tarn  an  abundance  of  life  even  now,  but  it  is  in 
hiding,  it  is  in  winter-retreat,  it  is  waiting.  And  as 
we  look  at  the  partial  covering  of  ice  another  thought 
rises  in  our  mind  which  lasts  us  all  the  way  home : 
the  thought  that  this  world,  in  spite  of  all  Man's 
cataclysms,  is  singularly  well  adapted  for  going  on. 
For  there  is  surely  food  for  reflection  in  the  fact 
that  fresh  water  is  anomalous  in  expanding,  not 
contracting,  when  it  is  near  its  freezing-point.  This 
brings  the  coldest  water  to  the  top,  thus  tending  to 


MIDWINTER  133 

lessen  the  loss  of  heat  from  the  warmer  water 
below.  The  coat  of  ice,  once  formed,  remains  on 
the  surface  by  its  buoyancy,  the  warmer  water 
below  is  kept  fluid,  and  the  life  of  plants  and  ani- 
mals is  able  to  continue.  That  floating  sheet  of  ice 
is  a  diagram  of  the  moving  equilibrium  of  the 
world. 


XVIII 
THE    MICROCOSM    OF    THE    EGG 

DARWIN  called  the  brain  of  the  ant  the 
most  marvelous  speck  of  matter  in  the 
universe.  It  is  so  intricate  for  its  size — less  than 
that  of  a  pin's-head;  it  is  the  repository  of  so 
many  ready-made  tricks.  But  even  more  marvelous 
than  the  ant's  brain  is  the  much  minuter  ant's  egg- 
cell  (what  we  buy  as  "ants'  eggs"  are  pupae  under- 
going metamorphosis),  which,  in  a  manner  that  we 
cannot  begin  to  imagine,  contains  the  potentiality 
of  the  whole  insect  and  of  all  its  instincts  as  well. 
The  more  we  know  about  the  ovum,  the  more  the 
wonder  grows.  It  may  be  of  interest,  then,  to  look 
for  a  little  into  the  pit  whence  we  were  digged, 
and  upon  the  rock  whence  we  were  hewn.  For, 
like  most  other  living  creatures,  we  all  begin  as 
fertilized  egg-cells.  A  convenient  up-to-date  ac- 
count of  the  whole  matter  will  be  found  in  Professor 
Brachet's  L'CEuf  (1917),  a  brilliant  course  of  lec- 
tures which  this  embryologist  of  Brussels  has  re- 
cently delivered  at  the  College  de  France. 

The  egg-cell,  or  ovum,  is  typically  a  very  minute 
living  unit.  The  dark-colored  ovum  of  the  frog 
is  about  one-tenth  of  an  inch  in  diameter,  but  this 
is  gigantic  compared  with  the  ovum  of  most 

134 


THE  MICROCOSM  OF  THE  EGG       135 

mammals,  where  a  common  size  is  one-tenth  of  a 
millimeter,  say  a  tenth  of  the  diameter  of  an  average 
pin's-head.  In  the  large  eggs  of  birds,  reptiles, 
sharks,  and  the  like,  the  bigness  is  due  to  the  accu- 
mulation of  a  huge  capital  of  yolk.  On  the  top  of 
this  there  lies  a  drop  of  formative  living  matter, 
like  a  miniature  watch-glass  turned  upside  down. 
The  egg-cell  of  a  whale,  containing  the  potentiality 
of  the  colossal  creature,  is  no  larger  than  fern 
seed;  and  it  is  worth  noticing  that  the  male-cell 
or  sperm-cell  is,  according  to  the  kind  of  animal, 
several  thousand  times  smaller  than  the  egg-cell, 
and  thousands  of  sperms  may  rush  around  in  a  drop 
suspended  from  the  head  of  a  pin. 

In  spite  of  its  minuteness,  the  egg-cell  contains 
many  different  kinds  of  components,  which  are 
often,  if  not  always,  disposed  in  zones  or  after 
some  specific  pattern.  According  to  one  school, 
the  regions  of  the  egg  differ  qualitatively,  some 
having  particular  "  organ-forming  substances " 
which  others  have  not;  according  to  another 
school,  the  regions  differ  quantitatively  in  the 
degree  of  concentration  and  in  the  rate  of  reaction 
of  the  constituent  formative  materials.  Probably 
the  truth  is  with  both  schools.  Delicate  experiment 
has  made  it  certain  that  in  some  egg-cells,  e.g.  those 
of  sea-squirts  (Tunicates)  and  sea-gooseberries 
(Ctenophores),  particular  areas  of  the  egg,  some- 
times distinguishable  by  their  color,  will  normally 
develop  into  particular  organs  of  the  animal.  On 
the  other  hand,  the  pattern  of  most  egg-cells  is  not 


136  SECRETS  OF  ANIMAL  LIFE 

to  be  compared,  as  Professor  Brachet  says,  to  a 
harlequin's  coat,  composed  of  non-interchangeable 
pieces.  For  a  part  of  an  egg  is  often  as  good  as  the 
whole,  in  the  early  stages  of  development  at  least; 
and  a  relatively  large  piece  of  the  ovum  may 
often  be  cut  off  without  doing  the  future  embryo 
any  harm.  Besides  the  nutritive  yolk,  which  the 
egg  usually  builds  up  from  materials  furnished  by 
the  parent,  it  elaborates,  as  M  Faure  Fremiet 
has  shown  in  a  unique  research,  a  variety  of  other 
chemical  substances  which  are  among  the  building- 
stones  of  future  structures.  And  besides  these 
bodies  which  the  egg-cell  makes  for  itself,  there  are 
often  ab  initio  others,  with  weird  names,  such  as 
mitochondria,  which  are  regarded  by  many  as 
definite  inheritance-vehicles. 

Lying  in  the  midst  of  the  complex  cell-substance, 
which  often  shows  an  intricate  microscopic  structure 
(reticular  or  otherwise),  there  is  a  nucleus — a  mi- 
crocosm within  a  microcosm.  For  inside  this  nu- 
cleus there  are  all  sorts  of  things,  notably  a  definite 
number  of  readily  stainable  bodies  or  chromo- 
somes, which  again  may  be  resolved  into  beads  of 
chromatin  embedded  on  pieces  of  a  transparent 
(linin)  ribbon.  The  number  of  these  chromosomes 
is  definite,  e.g.  24  for  mouse  and  lily,  and  each  cell 
throughout  the  whole  body  usually  adheres  to  the 
characteristic  number.  So  each  species,  like  the 
Beast,  has  its  number.  Some  say  that  a  white  man 
has  47  and  a  white  woman  48,  and  a  negro  only  22; 
but  in  case  any  political  advantage  be  taken  of  this 


THE  MICROCOSM  OF  THE  EGG      137 

statement,  we  hasten  to  add  that  48  is  also  the 
number  of  the  snail  and  of  one  of  the  varieties  of 
banana.  In  truth,  the  important  fact  is  not  the 
number  itself,  but  its  persistence;  and  that  is  only 
an  instance  of  the  doggedness  of  specificity. 

One  of  the  outstanding  results  of  the  intricate 
process  of  ripening  or  maturation  in  the  history  of 
the  germ-cells  is  that  the  number  of  chromosomes 
is  reduced  to  one-half.  When  the  sperm-cell 
and  the  egg-cell  unite  in  fertilization  the  normal 
number  is  restored.  In  the  case  of  the  egg-cell  the 
reduction  usually  takes  place  in  the  formation  of 
the  first  of  two  polar  bodies — minute  daughter-cells 
of  the  ovum  that  come  to  nothing.  If  the  chromo- 
somes of  the  egg-cell  be  compared  to  a  pack  of 
cards,  half  of  the  pack  may  be  said  to  be  thrown 
away  prior  to  the  beginning  of  each  individual  life. 
If  the  chromosomes  are  the  bearers  of  hereditary 
qualities,  the  halving  of  the  pack  may  be  one  of  the 
opportunities  for  fresh  permutations  and  com- 
binations, which  form  the  raw  material  of  evolu- 
tion. The  ripe  ovum,  after  a  brief  attempt  to  go  on 
actively  living,  sinks  into  static  equilibrium.  It  is 
paralyzed  by  its  own  waste-products  (auto-intoxi- 
cation), and  becomes  relatively  impermeable  to 
outside  influences. 

As  every  one  knows,  what  normally  reawakens 
a  certain  proportion  of  the  mature  ova  from  their 
inertia  is  fertilization.  This  implies  many  distinct 
occurrences.  ( i )  The  sperm-cell  enters  the  egg-cell 
and  there  is  an  intimate  and  orderly  union  of  the 


138          SECRETS  OF  ANIMAL  LIFE 

chromosomes,  which  probably  bear  respectively 
paternal  and  maternal  hereditary  qual ities.  Accord- 
ing to  Professor  Brachet  and  some  other  authorities 
the  sperm-cell  is  not  important  in  connection  with 
the  transmission  of  specific  characters — that  is  the 
ovum's  role,  but,  in  addition  to  its  chief  function 
as  "  an  agent  in  division,"  it  may  be  credited  with 
being  the  vehicle  of  minor  personal  features  char- 
acteristic of  the  male  parent.  This  view  is  a  blow 
to  proud  fathers,  but  it  is  probably  the  exaggera- 
tion of  an  element  of  truth  into  a  falsity.  (2)  The 
fertilization,  as  we  have  mentioned,  restores  the 
normal  quantity  of  chromatin  and  the  normal 
number  of  chromosomes.  In  some  cases,  especially 
among  insects,  it  has  been  proved  that  there  are  two 
kinds  of  sperm-cells,  one  contingent  with,  and  the 
other  contingent  without  a  special  sex-chromosome, 
and  that  the  sex  of  the  offspring  hangs  on  the 
fertilization.  Thus  an  even  number  of  chromosomes 
in  the  fertilized  ovum  may  mean  a  female  offspring, 
while  an  odd  number  may  mean  a  male.  In  other 
cases,  however,  the  sex  of  the  off  spring  is  determined 
by  the  physiological  character  of  the  egg-cell, 
quite  irrespective  of  fertilization.  Thus  Professor 
Oscar  Riddle  has  shown  in  pigeons  that  the  eggs  with 
less  intense  metabolism  and  greater  storage  capac- 
ity develop  into  females.  (3)  The  entrance  of  the 
sperm-cell  implies  the  advent  of  a  minute  body 
called  the  centrosome,  a  mountain-moving  mouse, 
which  divides  into  two,  and  plays  an  important  part 
in  the  subsequent  division,  acting,  as  it  has  been 


THE  MICROCOSM  OF  THE  EGG      139 

said,  as  the  weaver  at  the  loom,  the  paternal  and 
maternal  contributions  being  the  warp  and  woof 
of  the  future  web.  (4)  When  the  sperm-cell  enters, 
a  wave  of  contraction,  starting  from  the  upper  pole, 
passes  through  the  ovum,  and  a  small  quantitiy  of 
fluid  is  expelled  which  insinuates  itself  between  the 
surface  of  the  egg  and  the  innermost  layer  of  the 
egg-membranes.  (  5  )  Finally,  the  sperm-cell  sets  up 
awakening  changes  in  the  living  substance  of  the 
egg,  which  then  passes  from  static  to  dynamic 
equilibrium.  The  formative  materials  are  redis- 
tributed and  stabilized  in  a  direction  determined  by 
the  meridian  of  the  sperm's  entrance.  This  new 
architecture  is  respected  in  the  subsequent  cleavage 
of  the  developing  egg.  Another  effect  is  that  the 
living  substance  of  the  ovum  becomes  suddenly 
refractory  to  the  entrance  of  another  sperm-cell, 
which  would  be  apt  to  induce  monstrosity.  This 
"blocking"  of  the  egg-cell  is  sometimes  accom- 
plished by  the  contraction,  already  referred  to, 
which  shuts  a  little  gateway  (micropyle)  present  in 
the  egg-envelope  of  many  ova. 

One  of  the  most  interesting  chapters  in  modern 
biology  concerns  artificial  parthenogenesis,  i.e. 
experimental  ways  of  launching  an  unfertilized  egg 
on  the  voyage  of  development.  Most  bee-experts 
believe  that  unfertilized  eggs  laid  by  the  queen 
develop  into  drones,  who,  therefore,  have  a  mother 
but  no  father.  This  is  natural  parthenogenesis, 
and  there  are  many  other  instances.  But  it  is  now 
known  that  in  a  variety  of  cases,  from  sea-urchin  to 


140          SECRETS  OF  ANIMAL  LIFE 

frog,  artificial  parthenogenesis,  followed  by  normal 
development,  can  be  induced  in  egg-cells  which 
invariably  require  fertilization  in  the  ordinary 
course  of  nature.  Professor  Jacques  Loeb's  chief 
method  is  to  subject  the  ova,  say  of  sea-urchin 
or  starfish,  first  to  the  influence  of  some  fatty  acid, 
like  butyric,  which  leads  to  oxidations  in  the  cortex 
of  the  egg,  the  formation  of  a  membrane  of  fertiliza- 
tion, and  so  on.  The  egg  is  activated,  and  if  the 
process  continues  it  ends  in  disintegration  and  death. 
But  if  at  an  appropriate  time  the  activated  egg 
is  subjected  to  hypertonic  sea-water,  this  acts  as  a 
corrective  of  the  impending  dissolution,  and  brings 
the  egg  back  to  a  safe  path  of  normal  development. 
Professor  Yves  Delage's  chief  method  is  to  subject 
the  ova  of  sea-urchin  or  the  like  to  the  combined 
action  of  tannin  and  ammonia,  the  former  tending 
to  coagulate,  the  latter  tending  to  liquefy,  the 
colloid  substances  which  make  up  the  egg.  Most 
of  the  ova,  when  restored  to  sea-water,  develop 
and  form  normal  larvae;  in  two  or  three  cases  the 
adult  form  has  been  reached.  Bataillon's  chief 
method  is  to  prick  frogs'  eggs  with  a  very  fine 
stylet  of  glass  or  platinum,  and  then  wash  them 
with  blood.  The  first  event  provokes  activation; 
the  second  event  allows  the  entrance  of  an  organic 
center  (a  blood  corpuscle,  and  not  necessarily  a 
frog's!)  which  initiates  a  well-balanced  ovum- 
segmentation.  Two  or  three  parthenogenetically 
developed  frogs  have  been  reared ;  they  are  normal, 
and  of  both  sexes. 


THE  MICROCOSM  OF  THE  EGG       141 

Another  kind  of  experiment  shows  that  a  half  or 
less  may  be  as  good  as  a  whole.  By  delicate  meth- 
ods of  microscopic  vivisection,  Professor  Delage 
was  able  to  cut  off  non-nucleated  fragments  from 
a  sea-urchin  ovum.  They  accepted  fertilization, 
however,  and  developed  into  embryos.  In  many 
cases,  when  a  fertilized  egg-cell  has  divided  into  two 
cells,  these  can  be  shaken  apart  with  the  result 
that  each  develops  into  an  entire  animal.  If  in  the 
two-cell  stage  of  the  developing  frog  ovum,  one  cell 
be  punctured  with  a  heated  electric  needle,  the 
remaining  cell  will  develop  into  a  one-sided  hemi- 
embryo  or  into  a  half-sized  whole  embryo,  accord- 
ing as  the  punctured  ovum  is  kept  fixed  or  allowed 
to  move  (and  readjust  itself)  in  the  water.  Indeed, 
if  a  part  of  an  ovum  or  of  a  developing  ovum  is  to 
serve  as  the  equivalent  of  a  whole,  the  essential 
condition  seems  to  be  a  restoration  of  the  typical 
topography  and  a  re-establishment  of  the  pro- 
portions of  materials.  If  a  vessel  of  sea-water  con- 
taining developing  eggs  of  the  lancelet  be  shaken 
at  the  two-cell  stage,  the  result,  according  to  the 
amount  of  shaking,  will  be  a  double  supply  of  dwarf 
embryos,  or  a  set  of  Siamese  twins.  Even  at  the 
four-cell  stage,  the  shaking  will  result  in  numerous 
dwarf  embryos,  or  in  queer  Siamese  triplets  and 
quadruplets.  Perhaps,  however,  we  have  said 
enough  to  suggest  the  wonder  of  the  egg-cell,  and  to 
make  this  certainty  clear,  that  no  easy-going  view 
of  the  microcosm  is  in  the  direction  of  the  truth. 


XIX 
THE  CURVE  OF  LIFE 

TO  Huxley  it  seemed  that  one  of  the  most 
significant  characteristics  of  living  crea- 
tures was  their  "  cyclical  development."  From  a 
microscopic  egg-cell  an  embryo  plant  develops; 
the  ovule  becomes  a  seed,  the  seed  a  seedling;  by 
insensible  steps  there  is  formed  a  large  and  varied 
fabric  of  root  and  stem,  leaves  and  flowers.  But 
no  sooner  has  the  edifice  attained  completeness 
than  it  begins  to  crumble.  The  grass  withereth 
and  the  flower  thereof  fadeth,  and  soon  there  is 
nothing  left  but  the  seeds,  which  begin  the  cycle 
anew.  It  is,  Huxley  said,  "a  Sisyphsean  process, 
in  the  course  of  which  the  living  and  growing  plant 
passes  from  the  relative  simplicity  and  latent 
potentiality  of  the  seed  to  the  full  epiphany  of  a 
highly  differentiated  type,  thence  to  fall  back  to 
simplicity  and  potentiality  again."  So  is  it  also 
among  animals.  The  microscopic  egg-cell  divides 
and  redivides,  and  there  is  built  up  an  embryo.  This 
may  develop  steadily  and  directly  into  the  likeness 
of  its  kind;  or  it  may  give  rise  to  a  quite  divergent 
phase — a  larva  of  some  sort — such  as  caterpillar  or 
tadpole,  which  by  and  by  undergoes  metamorphosis 
and  gets  shunted  on  to  the  direct  line  of  ontogeny. 

142 


THE  CURVE  OF  LIFE  143 

Through  more  or  less  critical  phases  of  adolescence 
it  becomes  adult.  It  is  a  not  infrequent  achieve- 
ment to  lengthen  out  the  period  of  mature  strength, 
but  sooner  or  later  the  edifice  begins  to  crumble. 
This  creature's  life  is  counted  in  days  and  that 
other's  in  months;  we  reckon  ours  in  years  and  the 
Sequoia's  in  centuries,  but  there  is  for  most  an 
ascending  and  descending  curve  from  the  vita 
minima  of  the  egg-cell  (which  often  dies  in  a  few 
hours  if  it  be  not  fertilized)  to  the  vita  minima  of 
the  outworn  creature  if  the  conditions  of  life  admit 
of  senescence,  which  as  a  matter  of  fact  is  in  most 
cases  evaded  among  wild  animals.  But  part  of 
the  fascination  of  the  study  of  life-histories  is  to  be 
found  in  a  recognition  of  the  fact  that  they  often 
differ  from  one  another  as  different  forms  of  a  mel- 
ody do  when  the  "  time  "of  the  various  parts  is 
altered,  and  that  this  variation  in  rate  is  often  finely 
adaptive  to  particular  conditions — i.e.  is  a  solution 
of  special  problems  of  life.  The  morphologists  are 
beginning  to  discern  that  one  type  of  skull,  or  one 
shape  of  fish,  or  one  contour  of  leaf,  may  be  derived 
from  another  by  supposing  a  slight  deformation — 
let  us  say,  a  tilting — of  the  whole  architecture,  and 
the  idea  that  we  wish  to  illustrate  (it  is  essentially 
traceable  to  the  fertile  brain  of  Professor  Patrick 
Geddes)  is  that  one  creature's  life-history  often 
differs  from  another's  in  a  change  of  rate  or  rhythm, 
in  an  elongation  of  one  part  of  the  life-curve  and  a 
compression  of  another. 

A  familiar  kind  of  life-history  is  that  into  which 


144          SECRETS  OF  ANIMAL  LIFE 

a  prolonged  larval  period  has  been  interpolated. 
Out  of  the  egg-shell  of  a  cockroach  there  comes 
a  miniature  of  the  adult,  but  out  of  a  butterfly's 
there  emerges  a  minute  caterpillar  with  very  little 
hint  of  its  parentage.  It  feeds  and  grows  and 
molts  its  husk,  and  this  logical  sequence  is  repeated 
over  and  over  again.  The  caterpillar  gains  strength 
and  stores  up  nutritive  reserves;  it  undergoes  a 
remarkable  metamorphosis,  most  of  the  old  larval 
body  breaking  down  and  a  fresh  start  in  develop- 
ment being  made  on  a  new  architectural  plan. 
Eventually  the  winged  butterfly  emerges,  as  it  were, 
by  a  second  birth,  and  enters  upon  a  phase  of  life 
which  is  preoccupied  with  reproduction  and  only 
secondarily  (if  at  all)  concerned  with  nutrition. 
The  relatively  long  caterpillar  period  makes  the 
ecstasy  of  the  butterfly  possible.  A  very  remarkable 
achievement  has  resulted  from  the  lengthening  out 
of  the  larval  phase,  and  in  many  life-histories  we 
hear,  so  to  speak,  the  same  tune.  The  mayflies 
or  Ephemerides  are  often  almost  diagrammatic,  for 
many  have  two  or  three  years  of  subaquatic  larval 
life  and  two  or  three  days  (or  less)  of  aerial  and 
reproductive  activity.  In  the  sea-lamprey  we  find 
a  somewhat  similar  punctuation  of  life — but  it  is 
notably  improved  upon.  For  after  a  long  larval 
fluviatile  period,  sometimes  of  four  years,  there  is  a 
phase  of  vigorous  adolescence  and  adult  life  in  the 
sea.  But  the  curve  ends  in  the  same  way — an 
almost  vertical  drop  after  reproduction.  In  the 
common  eel  there  is  a  greatly  elongated  larval 


THE  CURVE  OF  LIFE  145 

period,  lasting  it  may  be  for  a  couple  of  years, 
during  which  the  fish  makes  its  long  journey,  often 
of  a  thousand  miles,  from  the  open  sea  to  the  rivers 
and  ponds,  and  there  is  a  long  youthful  growing 
period,  for  several  years,  when  energy  is  accumu- 
lated for  the  short  strictly  adult  period  which  in- 
volves a  return  journey  to  the  sea  and  ends  appar- 
ently in  death  as  the  nemesis  of  spawning. 

Another  type  of  life-history  implies  a  suppression 
of  the  larval  period  and  a  lengthening  out  of  the 
embryonic  development  within  the  egg-shell  or  egg- 
envelope.  A  good  instance  is  to  be  found  in  a  class 
of  unfamiliar  but  widespread  primitive  animals, 
known  as  Onychophora,  of  which  Peripatus  is  a 
representative  genus.  They  are  interesting  syn- 
thetic types  with  certain  features  of  insects  and 
others  of  segmented  worms;  they  are  doubtless 
survivors  from  very  ancient  days,  keeping  a  pre- 
carious foothold  in  many  parts  of  the  world  in 
virtue  of  their  shyness  and  their  nocturnal  habits. 
Now  all  these  characteristically  cryptozoic  creatures 
are  viviparous,  and  the  young  they  bring  forth  are 
from  birth  miniatures  of  the  adults.  Moreover, 
the  period  of  embryonic  development  is  prolonged, 
sometimes  lasting  a  year.  Contrasting  this  with 
the  life-history  of  a  higher  insect,  we  see  that  in 
the  latter  embryonic  development  is  shortened  to 
a  minimum  and  the  larval  phase  lengthened  out 
extraordinarily.  In  birds  the  time  that  the  parents 
can  afford  to  spend  in  brooding  is  limited  by  the 
conditions  of  food  supply,  temperature,  and  the  like, 


146  SECRETS  OF  ANIMAL  LIFE 

and  in  consequence  the  period  of  embryonic  de- 
velopment has  been  relatively  shortened  or  con- 
densed. The  cock  that  crows  in  the  morn  is,  on 
the  whole,  except  in  brain,  as  complex  a  creature 
as  the  cow  that  tosses  the  dog,  but  the  chick  breaks 
its  way  out  of  the  egg  after  three  weeks  of  incuba- 
tion, whereas  the  calf  is  carried  by  the  cow  for 
about  nine  months  of  antenatal  life.  In  the 
contrast  between  the  callow  nestling  type,  which 
corresponds  to  prolonged  infancy,  and  the  preco- 
cious chick  type,  which  corresponds  to  abbreviated 
infancy,  we  have  another  familiar  illustration  of  the 
elasticity  of  the  curve  of  life.  How  striking  is  the 
case  of  the  Mound-Builders,  where  the  mother-birds 
have  evaded  brooding  and  where  the  young,  hatched 
within  the  heap  of  fermenting  vegetation,  are  able 
to  fly  right  away.  The  great  majority  of  fishes  are 
oviparous,  with  both  embryonic  and  larval  phases 
in  the  water.  In  this  there  are  great  risks  and  the 
juvenile  mortality  is  enormous.  Yet,  as  there  are 
plenty  of  fry  to  spare,  most  species  of  modern  fishes 
continue  to  prosper.  But  how  vivid  is  the  contrast 
between  their  life-curve  and  that  of  the  whale,  with 
a  single  calf  slowly  developing  within  the  mother 
and  born  into  the  sea  a  fully-formed  and  richly 
endowed  cetacean.  Just  as  there  are  plants  which 
remain  for  life  like  half-opened  buds,  and  others 
which  flower  before  they  leaf,  and  so  forth,  so  there 
are  animals  which  have  a  long  youth  and  others  a 
long  maturity,  some  that  are  born  old  and  others 
that  die  young;  some  which  break  down  suddenly 


THE  CURVE  OF  LIFE  147 

in  their  prime  and  others  that  seem  to  have  no 
limit  (save  violent  death)  to  their  persistent  growth. 
It  is  a  question  of  vital  punctuation. 

Just  as  there  are  many  novels  but  only  a  few 
plots,  so  amid  an  apparent  multiplicity  of  life- 
histories  we  discern  but  a  few  main  types.  The 
details  may  seem  very  different,  but  they  are  often 
interpretable  as  due  to  a  lengthening  out  here  and 
a  condensation  there,  to  a  changing  of  the  time  of 
the  tune.  Let  us  briefly  consider  three  corollaries  of 
this  proposition.  ( i )  Just  as  there  are  in  organisms 
architectural  variations  which  find  expression  in 
spatial  rearrangements  of  materials  (comparable 
to  those  we  see  a  schoolboy  effecting  with  his 
"mechano"  toy,  out  of  which  he  constructs  now  a 
crane  and  again  a  bridge,  to-day  a  railway  truck 
and  to-morrow  an  aeroplane),  so  there  are  temporal 
variations  which  find  expression  in  changes  in  the 
rate  of  growth  and  development,  or  in  alterations 
in  the  rhythm  or  punctuation  of  life.  In  this  con- 
nection it  is  interesting  to  remember  that  in  the 
internal  secretions  (of  back-boned  animals  at  least) 
there  is  a  means  by  which  the  rate  of  growth  and 
development  can  be  automatically  regulated.  How 
suggestive,  for  instance,  is  the  result  of  Guder- 
natsch's  experiments  on  tadpoles,  that  a  thyroid 
diet  stimulates  differentiation  and  hinders  growth, 
while  a  thymus  diet  inhibits  differentiation  and 
lets  growth  go  on.  (2)  The  general  idea  is  that  the 
curve  of  life  is  like  a  discontinuously  elastic  thread 
wth  fixed  arcs  here  and  there,  and  that  the  tension 


148  SECRETS  OF  ANIMAL  LIFE 

of  the  several  parts  can  be  altered  in  adaptation  to 
particular  conditions.  This  is  part  of  the  tactics 
of  evolution,  and  it  is  interesting  to  observe  the 
diversity  of  the  problems  that  alterations  in  the 
tempo  of  life  are  made  to  solve.  The  open-sea 
larval  period  in  crabs  and  rock-lobster,  in  sea- 
urchins  and  starfishes,  secures  diffusion  and  saves 
the  delicate  young  life  from  the  intolerable  rough- 
and-tumble  conditions  of  the  shore.  The  swimming- 
bell  or  medusoid  period  (sexed)  in  the  life-history 
of  many  a  sedentary  asexual  zoophyte  or  hydroid 
colony  probably  secures  the  advantage  of  cross- 
fertilization.  The  very  general  suppression  of  the 
free-swimming  larval  stages  in  river  animals  (ex- 
cepting cases  such  as  insect  larvae,  where  gripping 
organs  are  well  developed)  is  evidently  an  adapta- 
tion against  the  risks  of  being  washed  down  to  the 
sea  or  being  borne  into  an  equally  fatal  stagnant 
backwater.  A  telescoping  of  not  only  larval  periods 
but  of  youth  itself  into  a  prolonged  embryonic 
development  may  mean  that  circumstances  are  too 
tyrannous  for  delicate  young  lives,  but  it  may  also 
mean,  as  in  many  mammals,  that  time  is  given  in 
the  long  antenatal  life  for  the  perfecting  of  a  fine 
organization,  able  from  birth,  in  many  cases,  to 
cope  with  the  exigencies  of  life.  Robert  Chambers, 
the  author  of  the  once  famous  Vestiges  of  Creation, 
was  surely  right  in  insisting  that  the  embryo's 
biding  its  time  within  the  womb  was  as  precious  to 
it  as  it  was  costly  to  the  mother.  It  meant  bigger 
and  better  brains.  In  the  prolonged  youth,  again, 


THE  CURVE  OF  LIFE  149 

of  some  other  mammals,  especially  those  with  a 
play-period,  there  is,  as  Dr.  Groos  and  Dr.  Chal- 
mers Mitchell  have  so  well  shown,  an  adaptation 
which  secures  the  breaking  down  of  rigid  instincts 
and  their  replacement  by  the  remembered  results  of 
free  and  intelligent  experiment.  (3)  While  man  is 
a  slowly  varying  creature,  changing  but  little  from 
age  to  age  in  the  organic  punctuation  of  his  life, 
he  is  eminently  plastic  or  modifiable,  and  therefore 
able,  probably  to  an  extent  unsuspected,  to  lengthen 
out  his  youth,  to  prolong  his  period  of  cerebral 
variability,  and  to  shorten  his  senescence.  In  all 
of  which  there  is  a  great  hope. 


XX 

REJUVENESCENCE 

SPRING  is  slow  of  coming  to  the  moor  of 
Dinnet,  but  on  ist  April,  1916,  it  arrived 
almost  without  warning — alighting,  like  some  great 
beneficent  bird,  from  a  distance.  We  had  gone  to 
sleep  in  what  seemed  like  midwinter;  it  had  been 
the  most  inhospitable  March  for  many  a  year;  we 
awoke  to  feel  the  West  wind  coming  in  at  the 
window,  and  the  simple  songs  of  yellow-hammers 
and  titmice,  and  a  new  smell  from  the  fir  trees; 
and  we  knew  that  the  winter  was  over  and  gone. 
Lochnagar  is  deep  in  snow,  and  all  the  little  hills 
around  are  black  and  white,  but  the  snow-wreaths 
could  be  seen  shriveling,  and  there  is  over  six 
feet  in  the  river  where  there  are  usually  but  three. 
To  a  stranger  from  the  South  the  spring  atmosphere 
of  the  day  would  seem  admirable,  but  he  would 
miss  the  note  of  vital  exuberance.  It  has  come 
too  quickly  for  that.  There  are  some  birds — black- 
headed  gulls,  oyster-catchers,  wagtails,  for  instance, 
at  the  flirtation  stage;  the  rooks,  lapwings,  and 
larks  have  got  past  it;  but  there  is  not  yet  any  hint 
of  the  great  orchestra  which  will  arrive  by  and  by. 
We  saw  on  our  walk  one  lamb,  one  tortoiseshell 
butterfly,  one  hairy  caterpillar,  and  less  parsi- 

150 


REJUVENESCENCE  151 

moniously  a  crowd  of  hive-bees  very  busy  at  the 
top  of  a  wayside  willow  whose  upper  catkins  are 
out.  Apart  from  the  catkins  and  the  gorse  (which 
does  not  count),  we  saw  not  one  opened  flower. 
The  leaf-buds  were  just  showing  on  broom  and 
briar;  the  twigs  of  the  larch  were  gilded  a  little 
and  the  birch  trees  had  put  on  their  purple,  but 
these  were  not  much  more  than  hints  of  the  reju- 
venescence that  we  know  to  be  sure  and  certain. 

The  biology  of  spring  is  a  book  with  many 
chapters,  and  it  is  but  one  chapter  whose  pages  we 
would  turn  to-day.  Spring  is  the  time  of  year  par- 
ticularly associated  with  a  capacity  that  many  living 
creatures  have  of  becoming  young  again — a  capacity 
that  Man  and  the  higher  animals  have  in  greater 
part  lost.  The  whole  question  has  recently  been 
brought  before  serious  students  of  biology  in  two 
remarkable  books  by  Professor  W.  M.  Child  of 
Chicago  (Senescence  and  Rejuvenescence*  and 
Individuality  in  Organisms2),  and  it  is  a  profitable 
subject  for  reflection,  not  least  for  those  who  have 
to-day  good  reason  for  finding  it  difficult  to  be  as 
gladsome  as  those  yellow-hammers,  or  as  rejuvenes- 
cent as  these  birch  trees.  In  the  world  for  which 
Man  is  primarily  responsible,  namely,  civilized  man- 
kind, domesticated  animals,  and  cultivated  plants, 
it  is  all  too  easy  to  find  examples  of  senility — aged 
people  who  are  pathetic  as  broken  harpsichords; 
woe-begone,  aged  horses  and  dull-eyed  wheezing 

1  Chicago  University  Press,  1915. 

2  Ibid.,  1916. 


152          SECRETS  OF  ANIMAL  LIFE 

dogs;  fruit-trees  smothered  in  lichen  and  rotting 
in  their  hearts.  Such  senility  marked  by  degenera- 
tion or  involution,  by  great  liability  to  disease  and 
by  an  ungearing  of  important  parts  of  the  organism, 
is  practically  unknown  in  wild  Nature  which  has 
not  suffered  from  Man's  interference.  Even  the 
Sequoias  with  their  two  thousand  years  are  not 
senile,  and  the  famous  Edinburgh  sea-anemone, 
which  lived  longer  than  the  average  human  span, 
did  not  show  its  age.  There  are  two  main  reasons 
for  this  absence  of  senility  in  Nature;  the  first  is 
that  the  conditions  of  the  struggle  for  existence 
are  such  that  senility  is  not  tolerated;  the  second 
is  that  the  average  duration  of  life  seems  to  have 
been  punctuated  in  reference  to  wide  issues,  namely, 
the  welfare  of  the  species.  Creatures  come  to  a 
natural  end  when  their  processes  of  rejuvenescence 
fail  hopelessly  to  keep  pace  with  their  processes  of 
senescence.  For  to  senescence  as  distinguished  from 
senility  the  great  majority  of  organisms  are  liable. 
To  the  question,  "  Why  do  we  grow  old  ?  "  many 
answers  have  been  given.  Metchnikoff  suggested 
that  we  are  poisoned  by  the  absorption  of  the 
products  of  bacterial  activity  in  the  large  intestine, 
for  this  brings  about  hardening  of  the  walls  of  the 
arteries  and  also  corrupts  our  bodyguard  of  wan- 
dering amoeboid  cells  or  phagocytes,  so  that  they 
become  traitors,  turning  upon  the  cells  of  the  cen- 
tral nervous  system.  Others  have  suggested  other 
modes  of  auto-intoxication.  To  some  it  has  seemed 
enough  to  refer  to  the  wear  and  tear  of  hard- worked 


REJUVENESCENCE  1 53 

organs  like  brain  and  heart,  liver  and  kidneys,  for 
a  chain  is  no  stronger  than  its  weakest  link.  Others 
have  referred  to  the  waning  activity  of  the  all- 
important  organs  of  internal  secretion,  and  others 
to  the  sobering  fact  that  there  is  no  multiplication 
or  replacement  of  the  cells  of  our  central  nervous 
system  after  a  very  early  date  in  our  life.  It  may  be 
pointed  out,  however,  that  most,  if  not  all,  of  the 
theories  break  down  because  they  do  not  admit  of 
all-round  application  (thus  it  is  plain  that  many 
animals  that  are  not  troubled  with  a  large  intestine 
nevertheless  grow  old),  and  furthermore  that  the 
theories  seize  on  symptoms  rather  than  on  causes; 
for  while  it  is  good  sense  to  refer  to  wear  and  tear, 
the  question  arises  why  all  animals  do  not  exhibit 
the  perfect  recuperation  to  which  some  at  least  have 
attained. 

Professor  Child  has  been  working  for  fifteen 
years  or  more  with  simple  creatures  called  Planarian 
worms,  which  he  has  come  to  know  with  con- 
siderable intimacy.  One  of  the  features  of  their 
life  which  he  brought  to  light  is  their  capacity  for 
periodically  becoming  young  again.  Thus  it  often 
happens  that  a  Planarian  separates  off  the  posterior 
third  or  quarter  of  its  body,  which  speedily  grows 
into  a  whole,  while  the  diminished  original  heals 
itself  and  grows  a  new  tail.  This  is  an  old  story, 
but  the  new  fact  is  that  in  the  reconstitution  of 
the  whole  from  the  part  there  is  a  remarkable 
process  of  rejuvenescence.  Instead  of  the  current 
of  life  being  slow,  it  is  very  rapid;  the  output  of 


154  SECRETS  OF  ANIMAL  LIFE 

carbonic  acid  (a  common  index  of  the  rate  of  me- 
tabolism), as  measured  by  Tashiro's  delicate  "bi- 
ometer,"  is  greater  than  usual;  and  the  piece  is  less 
susceptible  and  more  resistant  to  poisons  like 
cyanides  than  when  it  was  part  of  its  parent.  If 
these  be  qualities  of  youth,  then  this  regrowing 
fragment  is  again  young.  Similarly,  when  a 
Planarian  is  starved,  it  can  continue  living  on  its 
own  resources  for  several  months.  Its  cells  become 
smaller  and  they  also  become  fewer,  but  life  is  not 
surrendered.  This,  again,  is  an  old  story,  but  the 
new  fact  is  that  the  starveling  becomes  curiously 
young — a  quaint  biological  justification  of  asceti- 
cism— it  is  almost  born  again.  Such  facts  have  led 
Professor  Child  to  a  survey  of  the  animal  king- 
dom, the  result  of  which  is  to  show  that  there  is  a 
much  wider  occurrence  of  rejuvenescence  than 
has  been  hitherto  realized.  It  occurs  especially 
in  connection  with  vegetative  multiplication,  but 
there  are  other  occasions  in  which  de-differentiation 
sets  in,  and  the  creature  becomes  younger  in  whole 
or  in  part  by  lying  low  for  a  season.  Perhaps  this 
may  be  part  of  the  value  of  processes  of  dying-back 
and  rearrangement  which  occur  in  winter  in  some 
animals  and  in  many  plants. 

Senescence  is  an  all  but  universal  retardation  of 
the  rate  of  life,  a  diminution  of  vigor  and  resisting 
power,  and  there  can  be  little  doubt  that  Professor 
Child  is  right  in  regarding  it  as  the  necessary  conse- 
quence of  accumulation,  differentiation,  and  other 
stereotyping  changes  in  the  colloid  substratum 


REJUVENESCENCE  155 

which  forms  the  framework  of  the  chemico-physical 
basis  of  life.  Chemically  regarded,  living  means  the 
co-ordination  of  characteristic  chemical  changes, 
differing  in  nature  and  in  rate  in  different  creatures 
and  in  different  parts  of  the  same  creature;  but  as 
these  proceed  they  form  a  colloid  framework  in 
which  they  work.  As  the  complexity  of  the  frame- 
work increases,  and  the  stability  of  the  organism, 
so,  too,  the  effectiveness  of  its  chemical  reactions. 
Thus  the  earthworm  is  more  of  an  agent  than  the 
amoeba,  and  the  bird  more  than  the  earthworm. 
But  the  nemesis  is  senescence — the  tax  on  stability, 
and  rejuvenescence  is  the  attempt  at  evasion. 
In  the  Protozoa,  as  Weismann  and  others  have 
pointed  out,  the  recuperative  processes  are  so  perfect 
that  natural  death  need  never  occur;  the  stable 
mortal  parts  of  the  colloidal  substratum  can  be 
reduced  and  restored  piecemeal,  and  the  creature 
never  grows  old.  It  is  probable  that  the  same  is 
true  of  a  simple  animal  like  the  freshwater  Hydra, 
which  may  also  be  credited  with  immortality.  But 
as  life  became  more  worth  living,  and  the  organism 
more  of  an  agent,  it  became  more  and  more  difficult 
for  the  processes  of  rejuvenescence,  which  are 
always  going  on,  to  keep  pace  with  those  of  senes- 
cence, which,  to  tell  the  truth,  may  begin  before 
birth!  Then  it  became  necessary  to  have  special 
periods  for  rejuvenescence,  "  spring-cleanings  "  of 
the  organism,  and  we  see  these  in  the  de-differentia- 
tions and  new  beginnings  associated  with  budding 
and  the  like,  perhaps  even  in  such  striking  phe- 


156          SECRETS  OF  ANIMAL  LIFE 

nomena  as  the  return  to  an  almost  embryonic  state 
that  we  are  familiar  with  in  the  pupa-stage  in  the 
life-history  of  flies  and  some  other  insects  with 
complete  metamorphosis.  But  what  of  the  dis- 
tinctly higher  animals  and  man  himself,  where  there 
has  been  an  epoch-making  evolutionary  increase  in 
the  physiological  stability  of  the  protoplasmic  sub- 
stratum and  an  associated  heightening  of  the  degree 
of  individuation?  The  central  nervous  system  in 
particular  limits  the  capacity  for  rejuvenescence. 
"  For  his  high  degree  of  individuation  man  pays  the 
penalty  of  individual  death,  and  the  conditions  and 
processes  in  the  human  organism  which  lead  to 
death  in  the  end  are  the  conditions  and  processes 
which  make  man  what  he  is."  Professor  Child 
has  an  interesting  speculation,  in  support  of  which 
some  experimental  evidence  is  adduced,  that  the 
very  early  pre-differentiating  stages  of  embryonic 
life  in  some  complex  organisms,  where  the  indi- 
vidual certainly  fails  to  evade  senescence,  may  afford 
opportunities  for  rejuvenescence  at  the  very  start  of 
life — for  lessening  the  risk,  that  is  to  say,  of  heredi- 
tary stereotyping  or  of  being  born  old.  We  should 
think  that  there  were  many  opportunities  for  this 
sort  of  reorganization  at  the  beginning  of  every 
new  life  that  develops  from  a  fertilized  egg-cell. 
But  of  an  elixir  vitse  for  the  individual  there  seems 
little  prospect.  "  The  advance  of  knowledge  and  of 
experimental  technique  may  make  it  possible  at 
some  future  time  to  bring  about  a  greater  degree  of 
rejuvenescence  and  retardation  of  senescence  in 


REJUVENESCENCE  157 

man  and  the  higher  animals  than  is  now  possible, 
but  when  we  remember  that  the  present  condition 
of  the  protoplasmic  substratum  of  these  organisms 
is  the  result  of  millions  of  years  of  evolutionary 
equilibration,  we  cannot  but  admit  that  this  task 
may  prove  to  be  one  of  considerable  difficulty." 

We  should  just  think  it  will,  but  we  are  slow  to 
conclude  that  we  must  simply  say  as  of  old :  "  And 
so  from  hour  to  hour,  we  ripe  and  ripe;  and  then, 
from  hour  to  hour,  we  rot  and  rot."  For  in  the 
biological  facts  we  find  more  than  a  hint  that 
changes  are  lightsome;  that  habituations  age  us; 
that  new  work,  new  scenes,  new  play,  new  rest,  at 
the  worst  new  diet,  should  be  experimented  with; 
that  we  should  cultivate  in  our  pilgrimage  the  ad- 
venturous mood,  for  if  it  be  true  that  a  man  is  just 
as  old  as  his  arteries,  it  is  also  true  that  he  is  as 
young  as  his  mind  is.  Our  life  is,  we  suspect,  largely 
punctuated  beforehand,  but  certainly  not  wholly. 
We  can  put  in  commas,  and  we  have  a  sporting 
chance  of  inserting  semicolons.  In  any  case,  our 
effort  to  stave  off  senescence  is  likely  to  be  rewarded 
by  an  evasion  of  senility. 


XXI 
THE  BIOLOGY  OF  TWINS 

THE  path  of  light  is  often  strangely  circuit- 
ous, for  who  would  have  thought  that  the 
study  of  an  armadillo  would  illumine  the  problem  of 
human  twins?  That  this  is  so  has  been  vividly 
shown  by  Mr.  Horatio  Hackett  Newman  in  an 
entertaining  volume  entitled  The  Biology  of  Twins.* 
One  cannot  help  envying  him  the  story  he  has 
to  tell.  Not  uncommon  in  Texas  is  an  old-fashioned 
creature,  the  Nine-banded  Armadillo,  a  sort  of  liv- 
ing fossil  belonging  to  a  stock  unique  among 
mammals  in  having  bony  plates  in  its  skin.  Be- 
tween an  arched  cuirass  over  its  shoulders  and  a 
similar  shield  over  its  loins  it  has  nine  movable 
bands  of  bony  armor.  The  body  is  about  eighteen 
inches  in  length,  not  counting  the  pointed  armored 
head  with  mulish  ears  and  the  long  tapering  tail. 
Baskets  made  of  armadillo  carapace  with  the  tail 
arched  over  to  form  the  handle  are  common  curios 
in  the  New  World.  The  creature  is  mainly  in- 
sectivorous, and  hunts  at  night,  retiring  to  its 
deep  six-foot  burrow  during  the  day.  Its  armor 
is  defensive  against  the  thorns  and  spines  of  the 
arid  vegetation  amongst  which  it  lives,  and  stories 

1  Chicago  University  Press,  1917. 
158 


THE  BIOLOGY  OF  TWINS  159 

of  the  armadillo  rolling  up  into  a  ball  (a  pre- 
rogative of  the  Little  Armadillo)  "  are  totally  in- 
applicable to  this  species,  for  the  animal  turns  over 
on  its  back  and  kicks  viciously  and  effectively  with 
its  powerful  and  heavily  armed  feet."  But  beyond 
noting  that  the  young  ones  are  born  well  advanced 
and  able  to  walk  about  within  the  first  few  hours, 
we  must  not  say  anything  more  about  the  natural 
history  of  the  Nine-banded  Armadillo.  For  our 
present  purpose  the  important  fact  is  that  this  quaint 
creature  normally  and  habitually  produces  quad- 
ruplets— a  remarkable  fact  which  several  zoologists 
have  studied,  and  Mr.  Newman  most  thoroughly 
of  all. 

Many  mammals,  such  as  rabbits,  produce 
numerous  young  ones  at  once,  but  each  of  these 
develops  separately  from  an  egg-cell,  and  the 
phenomenon  of  multiparous  birth  has  nothing  to  do 
with  twinning.  That  term  is  appropriate  when 
a  creature  normally  uniparous,  such  as  cow  or  bat, 
gives  birth  simultaneously  to  two  offspring.  As 
every  one  knows,  these  may  be  quite  dissimilar,  or 
they  may  be  living  images  of  one  another,  in  which 
case  they  are  always  of  the  same  sex.  In  un- 
toward cases  twins  may  be  physically  continuous, 
as  in  the  "  Siamese  twins,"  and  one  member  of  the 
pair  may  be  to  a  varied  degree  degenerate  or  un- 
developed,— the  result  being  the  twin-monsters  of 
the  show  or  of  the  embryological  museum.  Some 
of  them  are  the  results  of  fission,  others  of  fusion. 
But  there  has  been  much  vagueness  and  uncertainty 


160  SECRETS  OF  ANIMAL  LIFE 

about  the  whole  subject  of  twinning,  and  we  wel- 
come the  light  that  has  come  from  the  armadillo. 

Mr.  Newman's  investigations  have  made  it  quite 
certain  that  the  quadruplets  of  the  Nine-banded 
Armadillo  are  all  simultaneously  produced  from  one 
egg,  within  a  common  birth-robe,  and  that  they 
are  always  of  the  same  sex.  In  a  neighboring 
species,  the  Hybrid  Armadillo,  believed  to  be  a 
recent  evolutionary  derivative  of  the  Nine-banded, 
the  number  of  " polyembryonic  offspring"  devel- 
oped from  one  egg  varies  from  seven  to  twelve, 
with  a  tendency  to  settle  down  to  eight — a  varia- 
bility which  suggests  that  the  peculiarity  in  question 
is  of  comparatively  recent  origin. 

When  the  egg  of  the  lancelet  at  the  two-cell  stage 
is  shaken  vigorously  in  the  sea-water  in  which  it 
floats,  the  two  cells  separate  and  form  two  half-sized 
embryos  and  larvae.  If  the  shaking  is  less  vigorous, 
so  that  the  two  cells  do  not  go  apart,  Professor 
E.  B.  Wilson  found  that  Siamese-twin  embryos  are 
formed.  Similarly  from  the  four-cell  stage  he  got 
four  dwarf  embryos  and  larvae,  or  queer  non-viable 
Siamese  quadruplets!  In  some  Ctenophores  or 
sea-gooseberries,  twinning  is  often  noticed  after 
storms,  for  the  first  two  cells  of  the  segmenting 
egg  are  shaken  apart.  But  it  is  not  by  the  disloca- 
tion of  the  first  four  cells  that  the  quadruplets  of 
the  Nine-banded  Armadillo  arise.  What  happens 
is  that  in  a  single  embryonic  vesicle  formed  by  the 
segmentation  of  the  fertilized  egg-cell,  and  after 
considerable  differentiation  has  occurred,  four 


THE  BIOLOGY  OF  TWINS  161 

secondary  growing-points  experience,  for  some 
reason  or  other,  physiological  isolation,  and  proceed 
to  develop  in  independence.  It  is  known  that  in- 
jections of  butyric  acid  and  some  other  reagents  into 
fish  embryos  may  bring  about  a  sort  of  dislocation 
or  partial  dissolution  of  the  germinal  area,  and 
that  this  "blastolysis "  results  in  monstrosities. 
As  butyric  acid  may  arise  in  a  mammal's  body  as 
the  results  of  deranged  carbohydrate  metabolism, 
Werber  has  suggested  a  physiological  theory  of  the 
origin  of  certain  kinds  of  monsters.  Now  it  may  be 
that  the  slight  isolation  or  insulation  of  four  foci 
in  the  germinal  vesicle  of  the  armadillo  is  a  step 
in  the  direction  of  blastolysis  which  has  not,  how- 
ever, crossed  the  limits  of  the  normal.  It  may  also 
be,  as  Mr.  Newman  suggests,  that  the  development 
of  two  offspring  from  one  egg  is  "  only  a  phase  of 
the  much  more  general  phenomenon  of  symmetrical 
division."  Thus  the  building  up  of  the  right  and 
left  sides  of  a  bilaterally  symmetrical  animal  is 
essentially  a  twinning  process.  It  is  a  very  interest- 
ing fact  that  of  twin-brothers  one  is  sometimes 
right-handed  and  the  other  left-handed. 

In  the  Nine-banded  Armadillo  quadruplets  spring 
from  one  egg,  but  it  is  a  curious  fact  that  in  the 
Hairy  Armadillo  (Euphractus)  twins  arise  from 
two  eggs  whose  external  birth-robes  (chorionic 
foetal  membranes)  fuse  together  secondarily.  Need- 
less to  say,  these  twins  may  be  of  different  sexes, 
while  the  quadruplets  of  Dasypus  are  always  of  one 
sex.  Here,  then,  we  have  an  instructive  hint  of 


162  SECRETS  OF  ANIMAL  LIFE 

what  doubtless  occurs  in  man;  duplicate  or  iden- 
tical twins  develop  from  one  egg;  dissimilar  or 
fraternal  twins  develop  from  two  separate  eggs. 
Outdoing  the  poly-embryony  of  the  Nine-banded 
and  the  Hybrid  armadillos  is  that  of  some  Hymeno- 
pterous  insects  (e.g.  Litomastix)  which  lay  their 
eggs  in  caterpillars  and  the  like,  for  from  each  egg 
there  develops  a  legion  of  embryos.  One  would  like 
also  to  speak  of  the  twinning  of  a  common  earth- 
worm, which  seems  to  occur  most  frequently  in 
warm  weather,  a  fact  to  be  taken  in  conjunction 
with  the  experimental  result  that  the  eggs  of  some 
sea-urchins  often  twin  in  large  numbers  when  the 
water  is  artificially  warmed.  Fascinating  in  its 
way,  but  taking  us  into  rather  deep  waters,  is  the 
case  of  the  "free-martin,"  a  sterile  and  abnormal 
female  calf  showing  some  masculine  features  which 
seem  to  be  due  to  hormones  borrowed  from  its  male 
co-twin,  the  two  of  them  arising,  undoubtedly,  from 
two  egg-cells. 

Another  point  of  great  interest  in  the  biology  of 
twins  was  raised  long  ago  (1876)  by  Mr.  Galton,1 
who  sought  to  find  in  the  history  of  twins  a  criterion 
of  the  relative  powers  of  "  nature  "  and  "  nurture." 
Will  duplicate  twins  become  unlike  if  subjected 
to  diverse  nurture?  Will  dissimilar  twins  become 
more  like  one  another  if  subjected  to  the  same 
nurture?  Mr.  Galton  investigated  about  eighty 
cases  of  close  similarity  between  twins,  affecting 
color  of  hair  and  eyes,  height  and  weight,  strength 
1  Journal  of  Anthropological  Institute,  1876. 


THE  BIOLOGY  OF  TWINS  163 

and  temperament,  intonation  and  handwriting. 
It  may  be  both  interesting  and  useful  to  recall  some 
of  the  extraordinary  illustrations  of  the  close  re- 
semblance of  duplicate  twins,  developed,  as  the 
armadillo  story  makes  clear,  from  one  egg.  Mr. 
Galton  tells  of  a  case  in  which  no  one,  not  even  the 
twins  themselves,  could  distinguish  their  hand- 
writing; of  another  case  in  which  "a  doubt  re- 
mains whether  the  children  were  not  changed  in 
their  bath,  and  the  presumed  A  is  not  really  B, 
and  vice  versa";  of  two  girls  who  used  regularly 
to  impose  on  their  music  teacher,  one  of  them  taking 
two  lessons  in  succession  when  the  other  wished 
a  whole  holiday;  of  a  schoolmaster  who,  to  make 
sure,  used  to  flog  both  twin-brothers  when  one  had 
sinned;  of  nine  cases  where  a  twin  addressed  his  or 
her  reflection  in  a  mirror  in  the  belief  that  it  was  the 
other  twin  in  person;  of  four  or  five  cases  of  doubt 
during  an  engagement  of  marriage;  and  of  a  quaint 
interchangeableness  of  expression,  "  that  often  gave 
to  each  the  effect  of  being  more  like  his  brother 
than  himself."  The  depth  of  the  constitutional 
sameness  is  said  to  be  sometimes  seen  in  the  twins 
sharing  some  special  ailment  at  the  same  time  or 
showing  the  same  exceptional  peculiarity.  "  Two 
twins,"  Galton  noted,  "  at  the  age  of  twenty-three 
were  attacked  by  toothache,  and  the  same  tooth 
had  to  be  extracted  in  each  case."  Two  closely 
similar  twin-brothers,  of  similar  tastes  and  pro- 
fession, died  of  Bright's  disease  within  seven  months 
of  each  other.  Sometimes  the  resemblance  is 


164  SECRETS  OF  ANIMAL  LIFE 

subtle  as  well  as  thorough.  "  One  twin,  A,  who 
happened  to  be  in  a  town  in  Scotland,  bought  a  set 
of  champagne  glasses  which  caught  his  attention, 
as  a  surprise  for  his  brother  B;  while,  at  the  same 
time,  B,  being  in  England,  bought  a  similar  set  of 
precisely  the  same  pattern  as  a  surprise  for  A." 
The  price  paid  was  doubtless  precisely  the  same. 
The  question  which  particularly  interested  Mr. 
Galton  was  how  far  diversity  of  environment  and 
occupation  affected  twins  who  showed,  to  begin 
with,  very  close  similarity.  In  some  cases  "  the 
resemblance  of  body  and  mind  continued  unaltered 
up  to  old  age,  notwithstanding  very  different  con- 
ditions of  life  ";  in  other  cases  there  was  divergence 
usually  traced  to  some  form  of  illness  affecting  one 
of  the  twins,  and  this  may  have  implied  an  initial 
difference  which  escaped  detection.  Nature  is 
stronger  than  nurture.  On  the  other  hand,  Mr. 
Galton  found  that  twins  which  did  not  at  first 
show  "  close  similarity  "  did  not  become  any  liker 
one  another  after  prolonged  influence  of  similar 
nurture.  "  There  is  no  escape  from  the  conclusion 
that  nature  prevails  enormously  over  nurture  when 
the  differences  of  nurture  do  not  exceed  what  is 
commonly  to  be  found  among  persons  of  the  same 
rank  of  society  and  in  the  same  country."  The 
cuckoo's  note  is  not  affected  by  its  early  instruction 
in  the  language  of  its  foster-parents.  It  should  be 
carefully  noticed,  however,  that  some  very  striking 
cases  are  on  record — e.g.,  in  the  late  Mr.  Benjamin 
Kidd's  Science  of  Power  (1918) — of  birds  and 


THE  BIOLOGY  OF  TWINS  165 

mammals  which  were  kept  from  earliest  youth  in 
peculiar  conditions  of  artificial  nurture  and  took  on 
the  ways  and  habits  of  their  unrelated  comrades; 
that  many  cases  are  known  among  children  where 
those  transplanted  early  from  deteriorative  to 
wholesome  conditions  have  developed  well ;  and  that 
the  changes  of  nurture  in  Gal  ton's  cases  were  within 
very  narrow  limits.  Hereditary  "  nature "  is 
indeed  the  seed-corn;  nurture  is  the  sunshine  and 
the  soil,  the  wind  and  the  rain.  When  both  com- 
ponents of  a  resultant  are  essential,  it  does  not  seem 
to  matter  very  much  which  we  call  the  more  im- 
portant. The  fundamental  factors  of  all  sorts  of 
characters  are  in  the  germ,  but  the  precise  expres- 
sion they  find  in  development  depends  in  some 
measure  on  the  nurture. 


XXII 
A  LIMB  FOR  A  LIFE 

AMONG  the  many  effective  ways  in  which 
animals  parry  the  thrusts  of  Death,  is 
there  one  more  daring  than  what  is  called  autotomy 
— the  surrender  of  a  part  which  often  saves  the 
whole?  Seemingly  daring,  one  must  say,  however, 
for  all  the  typical  cases  of  self-mutilation  are 
nowadays  reflex,  occurring  quite  apart  from  any 
deliberate  intention  to  sacrifice  intactness  for 
existence.  A  starfish,  seized  by  one  of  its  arms, 
surrenders  this  to  the  captor  and  escapes  with  the 
other  four,  regrowing  the  missing  part  at  its  infinite 
leisure.  But  since  the  starfish  has  not  a  single 
nerve-ganglion  in  its  body,  no  one  can  credit  it 
with  having  reflectively  recognized  that  it  is  better 
that  one  member  should  perish  than  that  the  whole 
life  should  be  lost.  That  the  surrender  of  an  arm 
is  effective  is  certain;  that  it  now  happens  reflexly 
is  also  certain;  but  to  conclude  that  this  interest- 
ing kind  of  response  to  a  frequently-recurring  risk 
was  historically  established  without  any  glimpse  of 
awareness  on  the  creature's  part  is  premature. 
We  have  to  remember,  for  instance,  that  brainless 
and  ganglionless  as  the  starfish  is,  it  shows,  e.g.,  in 
its  combat  with  a  sea-urchin,  a  capacity  for  per- 

166 


A  LIMB  FOR  A  LIFE  167 

sisting  in  a  prolonged  endeavor  along  a  line  which 
is  certainly  not  that  of  least  resistance,  which  leads 
to  a  reward  not  immediately,  but  only  eventually. 

Perhaps  Nature  would  not  have  put  her  natural 
selection  stamp  of  approval  on  the  asteroid's 
autotomy  if  individual  starfishes  had  not  approved 
of  it  themselves.  We  are  not  prepared  indeed  to 
say  what  form  the  brainless  creature's  approval 
might  take,  but  we  get  an  indication  of  it  perhaps 
in  approvals  given  by  our  subconscious  self.  Quite 
in  the  opposite  direction  is  another  saving-clause, 
that  cases  of  a  rat  or  a  stoat  cutting  itself  free  from 
a  trap  by  amputating  a  limb,  belong  to  a  category 
different  from  and  higher  than  that  of  starfishes  or 
crabs  which  illustrate  typical  autotomy. 

The  highest  level  at  which  autotomy  is  practised 
is  among  lizards,  many  of  which  need  but  little 
provocation  to  induce  them  to  surrender  their  tail 
to  their  assailant — an  expedient  that  often  saves 
their  life.  The  specific  name  of  our  British  limbless 
lizard  (Anguis  fragilis)  registers  the  uncanny  readi- 
ness with  which  it  surrenders  the  tail  of  its  snake- 
like  body.  That  lizards  have  taken  ages  to  bring 
their  life-saving  curtailment  to  perfection  seems 
probable,  especially  when  we  notice  that  in  many 
forms  there  is  a  special  breakage  area,  and  that 
a  weak  line  has  been  established  affecting  skin, 
muscles,  connective  tissue,  and  backbone.  Up  the 
middle  of  the  vertebra  there  is  a  soft  zone,  the 
breakage  plane,  across  which  the  tail  snaps  in  the 
autotomy.  What  is  lost  by  the  amputation  can 


168  SECRETS  OF  ANIMAL  LIFE 

be  regrown  at  leisure,  though  not  with  the  original 
finish.  Newts  and  salamanders  (and  the  tadpoles 
of  frogs  and  toads)  have  great  powers  of  regrowing 
parts  that  have  been  bitten  off,  but,  so  far  as  we 
know,  lizards  are  the  only  backboned  animals  that 
show  autotomy.  The  phenomenon  is  seen  again 
among  mollusks,  not  a  few  of  which  give  off  pieces 
of  their  body.  There  is  the  very  curious  case  of 
many  male  cuttlefishes  which  give  away  an  "  arm  " 
in  marriage — the  discharged  member  being  described 
by  some  old  zoologists  as  a  separate  creature  called 
"  Hectocotylus."  This  instance  should  perhaps  be 
kept  by  itself,  but  it  shows  that  the  capacity  of 
surrendering  parts  can  be  utilized  towards  various 
ends. 

Some  zoologists  have  tried  to  restrict  the  term 
"  autotomy "  to  the  surrender  of  what  should 
normally  be  retained,  but  it  does  not  seem  practi- 
cable to  maintain  this  strict  usage.  Many  of  the 
sea-slugs,  like  Tethys,  though  captured  ever  so 
gently,  proceed  to  disembarrass  themselves  of  finger- 
like  processes  on  their  back — strange  sops  to 
Cerberus.  Many  worms  also  show  a  strong  tendency 
to  self -mutilation  when  they  find  themselves  in  the 
unusual  conditions  of  capture.  One  throws  off  its 
tentacles,  another  its  pharynx;  one  offers  you  its 
head  and  another  its  tail.  We  look  on  with  helpless 
chagrin  while  a  fine  specimen  of  a  ribbon-worm, 
say  Cerebratulus,  lying  unharmed  in  a  basin  of  clean 
sea-water,  breaks  with  strong  muscular  contractions 
into  inch-long  pieces.  There  may  be  some  intense 


A  LIMB  FOR  A  LIFE  169 

disturbance  of  metabolism  which  we  do  not  under- 
stand; or  it  may  be  that  we  are  simply  witnessing 
an  extreme  tetanic  exhibition  of  what  occurs  in  a 
less  drastic  way  in  ordinary  life  and  with  life-saving 
results.  For  minor  losses  are  soon  made  good  and 
parts  may  become  wholes.  In  many  simple  worms 
the  periodic  surrender  of  a  posterior  piece  is  a 
regularized  mode  of  multiplication;  in  the  Palolo 
worm,  which  burrows  in  the  coral-reefs,  nearly  the 
whole  of  the  body  is  broken  off  at  the  breeding 
season  and  bursts  in  the  water,  liberating  tens  of 
thousands  of  germ-cells,  while  the  head  remains  in 
the  rock  and  makes  a  new  body  by  and  by.  Among 
starfishes,  brittle-stars,  feather-stars,  and  sea- 
cucumbers  there  is  an  extraordinary  prevalence  of 
autotomy.  A  starfish  may  jerk  off  each  of  its  five 
arms  seized  in  succession;  it  may  cast  off  an  injured 
or  parasitized  arm;  in  rare  cases  there  is  multiplica- 
tion by  division.  Sea-cucumbers  discharge  their 
viscera  in  the  spasms  of  capture  and  may  thus 
escape  from  an  astonished  foe.  The  replacement  of 
the  food-canal  is  sometimes  accomplished  in  ten 
days,  though  it  may  take  as  many  weeks.  The 
heart-urchin  often  gives  off  its  snapping  spines  when 
they  nip  the  skin  of  some  molester. 

One  often  sees  among  the  stubble  very  interesting, 
somewhat  spider-like  creatures  called  harvestmen 
(Phalangidse),  which  move  swiftly  (in  the  evening 
especially)  on  extraordinarily  lank  legs,  over  twenty 
times  the  length  of  the  body.  They  hunt  mostly 
by  night,  killing  and  sucking  small  insects  and 


170          SECRETS  OF  ANIMAL  LIFE 

drinking  drops  of  dew.  If  we  catch  one  by  the  leg 
it  surrenders  it  instantaneously  and  stalks  away. 
The  same  sort  of  profitable  autotomy  is  exhibited 
by  some  spiders  and  by  some  insects,  such  as 
grasshoppers,  crickets,  and  their  relatives.  A  quaint 
case  is  that  of  the  Termites,  or  white  ants,  which 
shed  their  wings  when  they  settle  down,  after  their 
so-called  "  nuptial  flight."  The  amputation  in  all 
these  cases  is  rapid  and  reflex,  and  there  is  no 
bleeding.  But  precise  knowledge  of  the  physiology 
of  autotomy  is  far  to  seek  except  in  the  case  of 
the  higher  Crustaceans,  to  which  we  shall  now  pass 
with  special  reference  to  the  recent  work  of  Mr.  J. 
Herbert  Paul.1 

( i )  It  has  been  recorded  in  regard  to  a  common 
amphipod  Crustacean,  called  Gammarus,  that  if  a 
leg  be  injured  the  animal  bites  it  down  to  the  base — 
a  quaintly  deliberate  autophagy.  (2)  If  a  prawn's 
leg  be  violently  seized,  the  animal  gives  a  vigorous 
jerk  with  its  tail  and  the  leg  breaks  off  at  the  base 
between  the  second  and  third  joint.  If  the  breakage 
fails,  the  prawn  may  be  seen  to  tug  at  the  limb 
with  its  jaws,  thus  harking  back  towards  autophagy. 
(3)  If  the  leg  of  a  lobster  or  crayfish  be  seized,  it 
always  breaks  at  the  level  of  a  groove  in  the  third 
basal  segment.  There  is  a  definite  breaking-plane. 
Moreover,  before  the  animal  strikes  with  its  tail,  a 
muscle  in  the  third  joint  weakens  the  limb  at  the 
level  of  the  breaking  groove  by  pulling  inwards 

1  Proc.  Royal  Soc.  Edinburgh,  xxxv.    (1918),  pp.  78-94,  4 
plates,  and  pp.  232-262,  29  figs. 


A  LIMB  FOR  A  LIFE  171 

parts  of  a  ring  of  calcareous  integument.  The 
amputation  is  more  complex  and  more  effective. 
The  autotomy  does  not  work  unless  the  limb  be 
gripped,  but  in  some  cases,  again,  the  animal  may 
pull  off  a  damaged  limb  with  the  help  of  one  of  the 
clawed  appendages.  (4)  In  hermit-crabs,  which 
shelter  their  soft  tail  in  a  borrowed  Gasteropod 
shell,  a  damaged  limb  is  amputated  simultaneously 
with  the  withdrawal  within  the  sheltering  shell. 
A  message  travels  to  the  nearest  ganglion  of  the 
ventral  nerve-cord;  an  answer  comes  back  com- 
manding violent  muscular  contraction  at  the  base  of 
the  leg;  and  in  a  moment  the  limb  is  severed.  But 
it  is  very  interesting  to  find  that  a  hermit-crab  upset 
by  being  removed  from  its  borrowed  shell  may  pluck 
at  an  injured  limb  with  its  forceps,  or  may  even  bite 
it  down  to  the  breaking-plane,  thus  falling  back  on 
autophagy.  (5)  It  is  in  crabs  that  the  autotomy 
reaches  perfection.  There  is  a  definite  breaking- 
plane,  a  line  of  weakness,  across1  the  second  basal 
joint;  the  breakage  is  due  to  the  forcible  antag- 
onism of  muscles  working  at  this  plane;  the  snap 
occurs  before  one  has  time  to  say  "  self -amputa- 
tion." 

In  the  shore-crab  and  the  edible-crab  the  limb 
cannot  break  off  unless  the  distal  part  of  it  be  pressed 
against  something,  such  as  the  animal's  own  shell 
or  a  stone;  in  the  swimming-crab  and  the  sand-crab 
even  the  point  d'appui  is  dispensed  with.  But 
perhaps  the  neatest  adaptation  in  crabs  is  the  dia- 
phragm or  bandage-membrane  which  stretches 


172  SECRETS  OF  ANIMAL  LIFE 

across  the  interior  of  the  hollow  limb  at  the  breaking- 
plane,  leaving  a  foramen  for  nerve  and  artery.  This 
diaphragm  consists  of  two  flaps,  and  when  autotomy 
occurs  "  these  are  forced  together  by  relative  change 
of  pressure  on  the  outer  side.'1  They  act  as  a  valve, 
"  and  the  moment  autotomy  takes  place  bleeding 
is  stopped/'  We  feel  ourselves  in  the  theater  of 
a  great  surgeon  whose  knife  staunches  as  it  cuts. 
We  are  reminded  also  of  the  partition  which  in 
autumn  grows  across  the  insertion  of  the  leaf-stalk 
and  closes  the  wound  as  it  separates  off  the  wither- 
ing leaf. 

We  see,  then,  that  the  surrender  of  a  limb  is  of 
common  occurrence  in  higher  Crustaceans.  It  often 
secures  escape;  it  also  avoids  bleeding  to  death 
if  a  limb  has  been  badly  wounded  by  an  enemy  or 
bruised  by  the  movement  of  stones  on  a  storm- 
swept  shore.  We  find,  moreover,  that  it  sometimes 
occurs  rather  roughly  and  sometimes  with  great 
neatness;  that  it  sometimes  involves  several  acts 
in  a  chain  and  sometimes  only  one.  And  the  very 
interesting  general  result  reached  by  Mr.  Herbert 
Paul's  fine  experiments  is  that  in  those  higher 
Crustaceans,  such  as  crabs,  where  the  breaking 
joint  is  structurally  most  complex,  the  physio- 
logical reflex  process  is  simplest.  It  is  a  single 
reflex,  whereas  in  lower  forms  there  may  be  several 
links  in  the  chain  of  events.  In  the  crab,  as  he  says, 
there  has  come  about  in  the  course  of  time  a  short- 
circuiting  of  a  "  current "  which  in  lower  forms 
has  a  much  lon^r  path.  Such  occasional  returns 


A  LIMB  FOR  A  LIFE  173 

to  autophagy  as  the  hermit-crab  exhibits  seem  to 
us  to  corroborate  our  suggestion  that  we  must  not 
conclude  from  the  simplicity  of  a  present-day  reflex 
that  the  process  has  evolved  without  any  factor 
of  awareness. 

What  is  the  evolutionist's  finding — provisional, 
of  course — in  regard  to  the  problem  of  autotomy? 
Perhaps  this:  (i)  that  a  capacity  for  breakage  is 
very  widespread  among  the  less  integrated  lower 
animals;  (2)  that  it  may  have  to  do  with  increase 
in  size  beyond  the  limits  of  nervous  control,  or 
with  an  inequality  in  the  intensity  of  metabolic 
processes  in  different  parts  of  the  body;  (3)  that  the 
giving  off  of  parts  may  be  useful  as  a  mode  of 
vegetative  multiplication;  as  a  means  of  getting  rid 
of  an  aged,  injured,  or  parasitized  portion;  and  as  a 
way  of  escaping  from  enemies;  and  (4)  that  it  has 
come  to  be  associated  with  a  subsequent  regenera- 
tion of  what  has  been  surrendered.  Given  these 
materials,  so  to  speak,  and  plenty  of  time  and  sift- 
ing, the  organism  can  perhaps  work  out  structural 
elaborations  as  finished  as  those  in  the  crab.  But  it 
is  at  least  a  tenable  theory  that  the  organism  is  a 
purposive  individuality  as  well  as  a  co-ordination 
of  chemical  reactions  taking  place  in  a  colloid 
substratum,  and  that  from  time  to  time  the  factor 
of  endeavor  and  the  will  to  live  has  entered  into 
the  evolutionary  process  with  varied  degrees  of 
self -awareness.  It  is  conceivable  also  that  what  in 
some  cases  required  to  begin  with — it  may  have  been 
for  a  million  years — genuine  behavior,  the  con- 


174  SECRETS  OF  ANIMAL  LIFE 

trolled  co-ordination  of  a  chain  of  activities,  so 
that  they  lead  to  an  effective  result,  may  in  the 
course  of  time  be  short-circuited  and  sink  to  the 
plane  of  reflexes,  leaving  the  organism  disem- 
barrassed and  free  for  fresh  adventure. 


XXIII 
LATENT  LIFE 

WHEN  a  saucer  of  paste  is  left  forgotten 
on  a  shelf  it  becomes  the  soil  for  an 
abundant  growth  of  minute  fungoid  plants  or 
molds.  But  in  many  cases  it  also  shows  a  popu- 
lation of  "  paste-eels,"  transparent  microscopic 
threadworms,  the  germs  of  which  have  been  wafted 
into  the  saucer  by  air-currents.  Millions  of  the 
closely  related  "  vinegar-eels  "  are  sometimes  to  be 
found  in  vinegar-cruets  which  have  been  left 
uncorked.  The  worms  seem  to  thrive  in  that 
strange  habitat,  and  they  make  the  vinegar  turbid 
with  their  multitudes.  Now,  the  paste-eels  and 
vinegar-eels  (and  other  "  Anguillulid  Nematodes  ") 
are  noteworthy  for  their  capacity  for  latent  life. 
They  can  remain  dried-up,  without  signs  of  any 
activity,  for  years,  and  yet  become  lively  again 
when  restored  to  moisture  and  other  appropriate 
conditions.  It  seems  that  some  of  them  can  endure 
the  "  suspended  animation "  for  fourteen  years, 
and  that  the  time  required  for  revivification  is 
proportionate  to  the  duration  of  the  latency.  The 
eel  worm  which  causes  "ear-cockles  "  in  wheat  is 
able  to  lie  latent  in  its  gall  for  over  twenty  years. 
The  same  phenomenon  is  illustrated  by  some  mites, 

175 


176  SECRETS  OF  ANIMAL  LIFE 

by  those  species  of  "  water-bears  "  that  live  in  moss, 
by  many  wheel -animalcules  or  rotifers,  by  some  of 
the  minute  Crustaceans  known  as  water-fleas,  and 
by  some  still  simpler  animals.  In  some  cases  what 
endures  is  the  whole  creature  as  such;  in  other 
cases  it  may  be  a  cyst  formed  inside  the  animal, 
or,  it  may  be,  just  an  egg  with  a  resistant  shell. 
From  dried  mud  taken  from  a  pond  and  kept  in  a 
box  for  ten  years,  one  can  by  putting  a  sample  into 
water  rear  many  little  creatures.  Professor  Giard 
found  that  the  eggs  of  the  large  freshwater 
Crustacean  called  Apus  could  survive  twelve  years 
of  drought.  Some  Protozoa  dried  on  paper  were 
revived  after  five  years.  It  is  difficult,  no  doubt, 
to  draw  a  strict  line  between  these  cases  of  latent 
life  and  other  conditions  of  lying  low,  as  in  the  true 
winter-sleep  or  hibernation  of  hedgehog  and  dor- 
mouse, or  the  winter-torpor  of  the  frogs  in  the  mud 
of  the  pond  and  the  snails  in  the  recesses  of  the  old 
wall,  or  the  lethargy  of  some  fishes  that  encapsule 
themselves  in  the  mud  during  the  dry  season  and 
suddenly  reappear  when  the  rains  return;  but 
what  marks  off  latent 'life  in  the  stricter  sense  is 
the  desiccation  of  the  organism  and  the  entire 
absence  of  any  positive  signs  of  "  life."  The  ques- 
tion is  whether  the  activities  which  we  sum  up  in  the 
word  "life"  have  come  to  a  standstill,  or  whether 
the  fire  is  still  burning,  but  very  low?  We  cannot 
dissociate  activity  from  our  idea  of  life,  but  here  is 
an  organization  so  dry  that  it  is  brittle,  in  which 
we  can  detect  no  movements,  not  even  chemical 


LATENT  LIFE  177 

changes,  and  yet  it  is  not  dead.  For  in  a  few  days 
we  may  revive  it  into  vigor,  or  may  nurse  into 
lively  development  the  cyst  or  germ  which  it  in- 
closes. The  riddle  stares  us  in  the  face  in  every 
bag  of  dry  seeds.  In  what  state  is  the  life  of  these 
seeds,  for  most  of  them  are  alive  in  this  sense  at 
least,  that  they  can  in  appropriate  conditions  give 
rise  to  living  plants?  This  brings  us  to  consider 
the  remarkable  experiments  recently  made  by  M. 
Paul  Becquerel. 

One  of  the  first  results  of  Becquerel's  work  was 
the  demonstration  of  the  extraordinary  imperme- 
ability of  the  envelopes  of  many  seeds.  Thus  the 
coats  of  the  naturally  dried  seeds  of  the  lupine  re- 
main impermeable  to  air  and  other  gases  for  two 
years.  They  are  also  impermeable  to  liquids,  such 
as  absolute  alcohol,  ether,  and  chloroform.  The 
gases  and  liquids  readily  soak  into  seeds  of  lupine, 
peas,  and  beans  whose  coats  have  been  taken  off, 
but  when  the  coats  are  left  on  they  are  for  a  long 
time  gas-proof  and  liquid-proof.  Very  careful 
experiments  with  naked  seeds  of  peas,  beans,  and 
lupine,  in  their  natural  state  of  dryness  (that  is, 
still  containing  a  minute  quantity  of  water),  showed 
that  after  a  certain  time  in  darkness  they  absorb 
traces  of  oxygen  and  liberate  traces  of  carbon 
dioxide.  But  this  gaseous  interchange  is  probably 
due  to  a  simple  chemical  oxidation  at  the  surface 
of  the  seed  and  not  to  an  attenuated  respiration. 
It  is  certain  that  seeds  do  not  necessarily  lose  their 
power  of  germinating  though  they  have  been  kept 


178  SECRETS  OF  ANIMAL  LIFE 

for  months  in  conditions  where  no  respiratory 
exchange  with  the  outer  world  was  possible. 
Becquerel  showed  that  seeds  deprived  by  an  air- 
pump  of  their  internal  atmosphere  and  kept  for 
a  year  under  mercury,  or  in  nitrogen  or  carbon 
dioxide,  or  in  a  nearly  complete  vacuum,  still  retain 
their  power  of  germinating.  What  is  this  life 
that  sulks  and  hides  itself,  but  will  not  die?  Life 
is  a  kind  of  activity,  a  series  of  correlated  reactions 
among  the  members  of  a  well-constituted  chemical 
firm,  and  taking  place  in  what  is  called  a  colloidal 
substratum  which  is  to  the  essential  activity  of  the 
protoplasm  as  the  bed  of  a  river  to  its  flow;  but  the 
activity  can  only  occur  in  an  appropriate  environ- 
ment of  air  and  moisture  and  the  like.  So  the 
question  is,  whether  the  latent  condition  implies 
a  total  suspension  of  vital  activities,  or  "an  ex- 
tremely sluggish,  intracellular,  anaerobic  life?" 
There  is  a  blockade,  but  does  the  firm  entirely 
suspend  operations,  or  does  it  keep  going  in  a  small 
way,  which  we  cannot  detect  ? 

The  great  French  physiologist  Claude  Bernard, 
to  whom  we  owe  the  term  "  latent  life,"  maintained, 
in  his  classic  work  on  "  The  phenomena  of  life  com- 
mon to  plants  and  animals,"  that  life  is  a  rela- 
tion between  organism  and  environment,  and  that 
in  dry  seeds  and  desiccated  animals  it  is  only  poten- 
tial. "It  exists  ready  to  manifest  itself  if  appro- 
priate external  conditions  are  available,  but  there 
is  not  the  slightest  manifestation  of  it  if  these  con- 
ditions are  lacking."  Living  is  not  attenuated 


LATENT  LIFE  179 

in  the  dry  seed;  it  has  stopped.  The  seed  is  like  a 
watch,  stopped  but  not  run  down,  which  a  shake 
might  set  going  again.  This  view  leads  one  to  the 
reflection  that  if  latent  life  is  an  entire  suspension 
of  protoplasmic  functions,  then  the  period  during 
which  revivification  is  possible  should  admit  of  great 
extension.  Now  when  we  inquire  into  the  facts 
we  find  that  the  limits  are  not  usually  very  long. 
This  suggests,  at  first  sight  at  least,  that  what  has 
happened  has  been  an  extreme  slowing  down,  not 
a  stoppage  of  the  vital  processes  or  metabolism. 
Some  of  the  dried  Anguillulid  worms  will  not  revive 
after  fourteen  years,  and  others  not  after  twenty- 
one,  and  there  are  limits  with  seeds  also.  The 
Sleeping  Beauty  cannot  sleep  indefinitely.  That 
distinguished  Egyptologist  M.  Maspero  never  suc- 
ceeded in  germinating  the  grains  of  wheat  which 
he  collected  in  the  tombs  of  the  Pharaohs,  though 
frauds  practised  on  the  inexpert  yielded  surprising 
results.  Becquerel's  careful  experiments  showed 
that  some  seeds  may  germinate  after  resting  in 
a  herbarium — a  hortus  siccus  indeed — for  eighty- 
seven  years,  but  the  tenure  of  latent  life  is  in  most 
cases  much  more  limited.  Twenty  germinations 
were  got  from  seeds  from  twenty-eight  to  eighty- 
seven  years  old,  but  most  were  towards  the  lower 
figure.  Even  very  tough  seeds,  which  Ewart  has 
called  "  macrobiotic,"  do  not  keep  their  germinative 
power  much  beyond  a  hundred  years.  In  many 
cases  among  plants  and  animals  the  limit  of  latent 
life  is  a  few  years.  This  seems  against  Claude 


180          SECRETS  OF  ANIMAL  LIFE 

Bernard's  view  that  vital  activity  is  wholly  sus- 
pended, for  why  should  there  be  a  limit,  if  this  be 
so?  It  is  quite  likely,  however,  that  the  limit 
is  determined  not  by  the  potency  of  the  essential 
protoplasm,  but  by  the  endurance  of  the  colloidal 
substratum — the  furnishings  of  the  chemical 
laboratory.  The  spring  of  the  stopped  watch  might 
in  the  course  of  time  undergo  some  molecular  change 
which  robbed  it  of  its  elasticity,  so  that  no  shake 
would  set  the  works  going  again.  Something  analo- 
gous may  occur  in  the  desiccated  organism. 

The  recent  experiments  clearly  show  that  subjec- 
tion to  conditions  utterly  hostile  to  the  persistence 
of  the  most  attenuated  of  vital  processes  or  metabo- 
lism is  not  necessarily  fatal.  Macquenne  kept 
parsnip  seeds  for  two  years  in  a  vacuum,  and 
made  them  as  dry  as  dry  could  be,  yet  they  were 
still  able  to  germinate.  Indeed,  they  retained  their 
sprouting  power  for  a  much  longer  time  than  con- 
trol seeds  kept  in  the  open  air.  The  same  conclusion 
is  suggested  by  similar  experiments  made  by  Bec- 
querel  and  also  by  the  results  of  subjecting  seeds 
to  very  low  temperatures.  Using  the  refrigerat- 
ing laboratory  or  "  cryogen  "  of  M.  Kammerlingh 
Onnes  at  Leyden,  he  subjected  naked  seeds  of 
lucerne,  mustard,  and  wheat  for  three  weeks  to  the 
temperature  of  liquid  air,  and  then  for  seventy- 
seven  hours  to  that  of  liquid  hydrogen  at  250° 
below  zero.  The  seeds  were  then  put  into  a  vacuum 
for  a  year.  Under  the  combined  influence  of  low 
temperature  arid  desiccation,  the  protoplasm  lost 


LATENT  LIFE  181 

its  state  of  colloidal  solution,  but,  in  spite  of  all, 
the  seeds  showed  a  high  percentage  of  germination ! 
Now,  as  Becquerel  says,  "life  without  water, 
without  air,  without  gaseous  exchanges,  without 
colloid  molecules  in  suspension  in  a  liquid,  appears 
paradoxical."  The  vital  current  is  frozen  hard, 
and  if  this  be  so  we  are  forced  to  the  conclusion 
that  life  is  not  bound  to  be  quite  continuous  until 
death  overtakes  it.  It  can  stop  and  begin  again. 
It  is  not  to  be  supposed  that  the  composition  of 
that  chemical  firm  which  we  call  protoplasm  has 
been  altered,  or  that  any  of  the  component  molecules 
have  suffered  disintegration.  That  way  death  lies. 
But  there  has  been  a  physical  check,  like  the  freez- 
ing of  a  stream,  from  which  recovery  is  possible 
within  limits.  One  would  like  to  see  Becquerel's 
experiments  extended  to  the  animal  world,  where 
the  phenomena  may  be  different;  but  the  evidence 
from  seeds  points  to  the  conclusion  that  life  may 
be  interrupted  without  destroying  its  power  of 
resuscitation. 

As  Becquerel  points  out,  the  capacity  for  lying 
low  is  no  mere  curiosity,  it  has  significance  in  the 
struggle  for  existence.  It  enables  organisms  to  bide 
their  time,  to  bend  to  the  storm,  to  wait  and  see. 
Many  minute  creatures  get  carried  about  in  a  state 
of  latent  life;  others  rest  in  quietness,  evading  a 
hopeless  struggle,  and  if  propitious  conditions  are 
restored  in  time,  they  do  not  lose  their  reward. 
"  Latent  life  is  a  true  Providence  for  the  terrestrial 
conservation  of  organisms."  Becquerel  suggests 


182  SECRETS  OF  ANIMAL  LIFE 

that  if  the  sun  were  extinguished  and  all  the  gases 
of  our  atmosphere  disappeared,  seeds  and  germs, 
eggs  and  spores  of  organisms,  in  the  state  of  latent 
life,  might  linger  on  for  a  long  time  on  the  surface 
of  the  "  frozen,  uninhabitable  planet,  wandering 
in  the  darkness  of  cosmic  space."  It  is  possible 
that  under  the  influence  of  the  radiations  of  a  new 
system  the  frozen  streams  of  protoplasm  might 
thaw  and  flow  again;  it  is  possible  that  a  shattering 
of  the  derelict  by  collision  or  explosion  might  sow 
new  worlds  with  the  seeds  of  old  life. 


XXIV 

THE  STORING  INSTINCT 

THERE  are  various  ways  in  which  animals 
meet  or  circumvent  impending  seasonal 
scarcity.  Many  go  into  winter  quarters,  and, 
reducing  their  expenditure  to  a  minimum,  lie  low 
till  the  spring  calls  them  again  to  action.  Others, 
like  the  wolves,  continue  to  live  dangerously,  and 
simply  intensify  the  keenness  of  their  hunting. 
Some,  like  the  ermine  and  the  ptarmigan,  don  a 
white  dress,  which  is  not  criffly  physiologically  best 
for  warm-blooded  creatures  in  very  cold  weather, 
but  gives  them  a  garment  of  invisibility  against  the 
background  of  snow.  Others  solve  the  problem 
by  a  change  of  habitat — notably  the  migratory 
birds,  which  come  from  the  snow-covered  moors 
to  the  open  shore  and  the  fields  adjacent,  or  "  wing 
their  way  from  cloud  to  cloud  down  the  long  wind  " 
to  "  warmer  lands  and  coasts  that  keep  the  sun." 
There  are  several  other  solutions  of  the  problem — 
to  curl  up  and  die  is  to  decline  to  consider  it — 
and  one  of  these  is  to  lay  up  stores,  to  hoard,  to 
save.  Many  animals  do  this  inside  their  bodies, 
and  what  are  called  "  hibernating  glands  "  and  the 
like  are  internal  stores  for  the  evil  day,  but  we 
shall  confine  our  attention  to  external  savings. 

183 


184          SECRETS  OF  ANIMAL  LIFE 

A  highly  specialized  storing  routine  like  that  of 
hive-bees  always  gives  one  at  first  an  impression 
of  the  inexplicable — even  magical.  It  is  wiser 
to  start  from  much  simpler  collecting  industries, 
for  an  elaborate  instinctive  capacity  is  probably 
the  result  of  adding  on  one  embellishment  after 
another  to  a  broad  commonplace  foundation,  of 
carrying  on  to  a  fine  issue  a  kind  of  behavior 
which  in  its  rudiments  is  shared  by  many.  A 
beginning  of  storing  may  be  looked  for,  perhaps,  in 
activities  like  those  of  earthworms,  which  collect 
leaves  and  drag  them  down  into  their  burrows, 
at  once  making  these  more  comfortable  and  pro- 
viding a  supply  of  food  for  the  rainy  day.  It  is 
surely  the  acquisitive  habit  that  they  have,  these 
earthworms,  for  we  got  more  than  fourscore  leaflets 
from  one  burrow,  and  we  have  often  seen  feathers 
as  well  as  leaves  being  taken  underground.  We 
would  suggest  that  one  of  the  roots  of  the  more 
specialized  storing  activities,  which  have  a  definite 
reference  to  an  on-coming  scarce  time,  is  to  be 
found  in  a  generalized  acquisitiveness  like  that  of 
the  earthworms,  whose  importance  Gilbert  White 
and  Charles  Darwin  were  at  one  in  recognizing. 

It  is  among  insects,  however,  that  we  find  an 
inclined  plane  of  storing  activities  that  lead  even- 
tually to  the  climax  illustrated  by  hive-bees  and 
by  some  of  the  ants.  Many  visitors  to  the  Medi- 
terranean region  have  admired  the  industry  of  the 
scarabees  who  roll  marble-sized  balls  of  dung  to  their 
holes,  and  there  gnaw  at  them  continuously  till  all 


THE  STORING  INSTINCT  185 

is  consumed.  In  this  there  is,  indeed,  only  the  first 
stage  of  storing,  but  the  late  M.  Henri  Fabre  de- 
scribed in  his  inimitable  way  how  the  mother 
scarabee  molds  a  pear-shaped  mass  and  deposits 
at  the  narrow  end  an  egg  which  occupies  a  special 
hatching  chamber  and  has  beside  it  a  special  first 
meal  for  the  emerging  grub!  Here  it  is  not  difficult 
to  imagine  the  step  from  collecting  for  self  to  collect- 
ing for  others,  and  a  great,  interest  is  attached  to 
Fabre's  observations  of  the  Spanish  Copris  and  some 
related  dung-beetles  which  are  unique  among  non- 
social  insects,  inasmuch  as  the  mother  survives  to 
see  the  emergence  and  complete  metamorphosis 
of  the  family  (a  very  small  one)  for  whose  early 
sustenance  she  has  industriously  stored.  It  seems 
to  us  reasonable  to  suppose  that  this  represents  an 
old-fashioned  state  of  affairs,  and  that  the  ordinary 
occurrence  (that  the  mother,  among  the  higher 
orders  of  insects,  does  not  survive  to  see  her  young 
in  the  perfect  state)  is  a  secondary  punctuation  of 
the  life-history. 

There  is  an  evolutionist  gratification  in  studying 
the  storing  activities  of  bees,  for  they  are  exhibited 
in  such  varied  degrees  of  elaboration  by  different 
types.  Among  the  solitary  bees  the  mother  makes  a 
store  for  the  brood  which  she  never  survives  to  see; 
among  humble-bees  the  store  is  begun  by  the 
mother  but  continued  by  her  worker-children, 
and  there  are  species  (beyond  British  bounds)  in 
which  at  least  a  part  of  the  society  survives  the 
winter:  in  tropical  species  of  the  bees  generically 


186          SECRETS  OF  ANIMAL  LIFE 

called  Melipona  and  Trigona  there  are  permanent 
societies  but  with  imperfect  combs;  in  the  hive- 
bees  we  have  to  do  with  permanent  societies  and 
with  perfect  combs.  The  elaborate  storing,  carried 
to  abnormal  exuberance  under  man's  domesticating 
tutelage,  is  correlated  with  surviving  the  winter — 
i.e.  with  permanence,  and  with  the  survival  of  the 
mothers  after  the  adolescence  of  their  offspring — 
i.e.  with  the  possibility  of  social  tradition.  The 
transition  from  purely  domestic  storing  to  social 
storing  illustrated  by  the  bees  on  the  instinctive 
level  is  closely  paralleled  by  what  has  happened 
in  mankind  on  the  intelligent  level. 

It  is  impossible  to  think  of  storing  without  a 
vision  of  Solomon's  ant  "  which,  having  no  guide, 
overseer,  or  ruler,  provideth  her  meat  in  the  sum- 
mer, and  gathereth  her  food  in  the  harvest."  And, 
as  among  bees,  we  find  all  grades  among  ants  from 
those  that  do  not  store  at  all  to  those  that  make  a 
fine  art  of  it.  But  every  naturalist  must  put  the 
brake  on  when  he  begins  to  descant  on  the  pismires, 
and  we  shall  confine  ourselves  to  one  illustration. 
According  to  recent  studies  of  the  common  Mediter- 
ranean ant,  Aphcenogaster  barbarus,  the  seeds  which 
are  collected  are  kept  for  a  time  dry  and  are  eventu- 
ally put  out  in  the  rain  so  that  they  begin  to  germi- 
nate. This  has  the  advantage  of  bursting  the  hard 
seed-coats,  and  in  some  cases  of  starting  processes 
of  fermentation.  At  a  certain  stage,  however,  the 
ants  kill  the  embryo-plant  by  biting  off  the  radicle 
or  other  parts,  and  the  seeds  are  dried  again  in 


THE  STORING  INSTINCT  1ST 

the  sun.  According  to  Neger  the  dried  seeds,  of 
some  leguminous  plants  for  instance,  are  then  taken 
back  into  the  nest  and  chewed  into  dough.  This  is 
dried  once  again  in  the  sun  in  the  form  of  little 
biscuits,  which  are  eventually  put  into  the  cup- 
board. It  is  probable  that  different  kinds  of  seeds 
receive  different  treatment,  and  in  some  cases  it 
seems  that  the  stored  material  is  not  eaten  after 
all,  but  is  used  as  a  culture  for  molds  (e.g.  Asper- 
gillus  niger)  of  which  the  ants  are  very  fond.  It  is 
a  very  interesting  fact  that  a  utilization  of  fungoid 
growths — remotely  comparable  to  man's  mushroom 
beds — is  exhibited  by  a  number  of  quite  unrelated 
animals — namely,  by  certain  ants,  termites,  beetles, 
and  mites. 

Among  backboned  animals  it  is  difficult  to  find 
convincing  instances  of  storing  until  we  come  to 
birds  and  mammals.  Apart  from  the  numerous 
birds  that  store  food  in  their  crops,  sometimes  so 
exuberantly  that  they  cannot  fly,  there  are  some 
that  may  be  said  to  lay  up  nutritive  savings  outside 
of  themselves.  The  large  Eagle  Owl,  which  occa- 
sionally visits  Britain,  often  gathers  a  huge  super- 
fluity of  food  (including  hares  and  rabbits,  poultry 
and  pigeons)  for  his  mate  and  offspring;  and 
peasants  have  been  known  to  utilize  him  as  Elijah 
his  ravens.  There  is  an  old  tale  that  ptarmigan 
make  stores  of  buds  and  berries  beneath  the  snow, 
but  there  is  no  doubt  that  at  least  two  species  of 
woodpeckers  store  acorns,  sticking  them  firmly 
into  holes  which  are  bored  "  for  the  purpose  "  in  the 


188          SECRETS  OF  ANIMAL  LIFE 

tree  stems.  This  is  all  the  more  interesting  if  it  be 
true  that  what  the  woodpeckers  really  eat  is  not  the 
acorn  but  a  kind  of  grub  that  develops  inside  it. 

Not  a  few  mammals  are  in  the  habit  of  hiding 
away  surplus  food,  and  it  is  easy  to  imagine  how 
this  might  lead  on  to  a  more  definite  storing  instinct 
such  as  squirrels  exhibit.  In  a  number  of  different 
hoards  the  squirrel  hides  hazel-nuts,  beech-nuts, 
and  acorns,  and  these  may  be  a  stand-by  in  the 
hard  times  of  winter  when  the  beautiful  creature, 
who  is  not  a  true  hibernator,  is  unable  to  sleep  away 
its  hunger,  or  when  the  young  ones,  who  remain 
for  a  long  time  in  the  company  of  their  parents, 
plead  for  food.  In  some  mild  parts  of  the  country 
the  squirrel's  storing  instinct  seems  to  remain  un- 
developed. There  are  other  mammals,  such  as  the 
marmots,  who  make  their  burrows  comfortable 
with  grass  and  shut  the  door  when  winter  knocks; 
it  is  again  easy  to  see  that  this  might  lead  on  to  a 
definite  hoarding  of  food  supplies.  Such  hoarding 
is  well  illustrated  by  some  of  the  light-sleepers, 
such  as  dormice,  who  awaken  from  their  hibernation 
whenever  the  weather  is  mild  and  are  then  inclined 

% 

to  have  something  to  eat.  In  the  burrow  of  the 
hamster  several  store-chambers  are  made,  and 
grain,  as  well  as  hay,  is  accumulated  in  considerable 
quantity.  We  read  that  the  people  of  Kamschatka 
rob  the  granaries  made  by  one  of  the  voles  (Micro- 
tus  (zconomicus) ,  and  that  the  Mongolian  herdsman 
brings  his  cow  in  autumn  to  eat  the  haystacks 
which  are  so  diligently  built  in  the  summer  months 


THE  STORING  INSTINCT  189 

by  the  quaint  tailless  hares.  We  have  not  been  able 
to  verify  in  the  field  what  has  been  circumstantially 
described,  that  moles  make  collections  of  decapi- 
tated earthworms — a  store  for  days  when  the 
ground  is  gripped  by  unusually  hard  frost.  We 
are  told  that  these  collected  earthworms  form  a 
living  larder,  unable  (as  they  could  in  summer)  to 
regrow  their  lost  heads,  and  therefore  unable  to 
crawl  away.  As  moles  are  experts  in  dealing  with 
earthworms  and  as  decapitation  interferes  with  co- 
ordinated movements,  there  is  nothing  incredible  in 
the  story.  But  it  is  a  grim  one ! 

We  have  seen,  then,  that  at  many  different 
levels  in  the  animal  kingdom  a  storing  instinct  has 
developed.  When  we  turn  to  man,  pre-eminent 
among  creatures,  we  find  very  little  evidence  of  any 
such  instinct.  This  seems  the  more  remarkable 
since  in  North  Temperate  countries  prevision  of 
and  provision  for  seasonal  scarcity  must  have  been 
for  untold  ages  of  life-saving  importance.  It  is 
possible  that  the  habit  of  saving  and  storing  was 
sustained  from  generation  to  generation  by  a 
domestic  tradition  which  has  gradually  become  en- 
feebled as  industrial  life,  facilities  of  transport,  and 
communal  storage  made  man  in  great  measure 
independent  of  local  and  temporary  scarcity.  The 
duty  of  saving  and  storing  was  gradually  shifted 
from  domestic  to  social  shoulders.  As  one  would 
expect,  the  domestic  tradition  is  stronger  to-day  in 
rural  than  in  urban  conditions,  for  the  man  with  a 
multitude  of  diverse  lives  in  his  charge  is  doomed 


190  SECRETS  OF  ANIMAL  LIFE 

to  disaster  and  forced  to  cruelty  if  he  does  not 
habitually  look  ahead.  The  relative  enfeeblement 
of  the  tradition  or  the  instinct  to  store  and  save 
may  in  critical  times  of  shortage  imperil  national 
welfare,  and  one  can  but  hope  that  in  this,  as  in 
parallel  cases,  there  will  be  a  replacement  of  in- 
stinctive or  traditional  habit  by  deliberate  rational 
purpose.  As  society  develops  it  is  ever  shedding 
the  unplastic  and  the  incongruent,  as  a  growing  lob- 
ster molts  its  encumbering  sherd.  But  in  putting  on 
a  new  garment  adapted  to  changed  times  and 
changed  folk-ways,  it  is  ours  to  make  sure  that  it  be 
not  less  effective  than  was  the  old-fashioned  jacket 
of  thrift. 


XXV 
THE  ROVING  IMPULSE 

ONE  of  the  recent  studies  in  human  heredity 
which  we  owe  to  the  energy  of  Dr.  C.  B. 
Davenport  and  the  generosity  of  the  supporters  of 
the  Station  for  Experimental  Evolution  at  Cold 
Spring  Harbor,  Long  Island,  concerns  those 
interesting  variants  who  are  called  "  rovers."  In 
a  marked  and  specific  way  they  are  restless  and  dis- 
inclined to  settle  down,  they  run  away  from  home, 
they  play  truant  from  school,  they  suddenly  resign 
good  situations,  they  disappear  for  years,  they  are 
"  rolling-stones "  and  in  extreme  cases  fugitives 
and  vagabonds  on  the  earth.  To  a  greater  or  less 
extent  their  life  is  swayed  by  a  wandering  impulse 
which  now  and  again  becomes  irresistible.  When 
the  impulse  is  strong  and  well-marked  its  expression 
is  spoken  of  as  nomadism,  and  it  appears  to  be  in 
a  high  degree  heritable.  It  may  find  outcrop  in 
a  quite  pathological  "  fugue"  when  the  wanderer  is 
found  far  from  home  in  a  dazed  or  excited  state,  or 
in  a  harmless  passion  for  travel  and  exploration, 
but  it  seems  to  be  a  specific  bent.  It  finds  expression 
in  children  more  frequently  than  in  adults,  it  is 
commoner  among  men  than  among  women,  it  is 
commonest  of  all  during  adolescence.  But  the 

191 


192  SECRETS  OF  ANIMAL  LIFE 

word  "  nomadism "  loses  in  value  if  it  is  laxly 
applied,  as  some  investigators  have  done,  to  com- 
mercial travelers,  peddlers,  missionaries,  fugitives 
from  justice,  crusaders,  and  Sioux  Indians !  When 
Herbert  Spencer  was  thirteen  he  ran  away  from  his 
uncle's  house  and  made  for  home,  walking  48 
miles  on  the  first  day,  47  miles  on  the  second,  and 
we  do  not  know  how  many  on  the  third.  But  there 
is  not  any  reason  to  think  of  the  young  philoso- 
pher as  a  nomad;  it  is  enough  to  know  that  he  was 
home-sick,  and  that  he  was  moved  by  a  sense  of 
having  been  unjustly  treated. 

The  first  question  is  as  to  the  reality  of  a  well- 
defined  idiosyncrasy  which  may  be  called  a  roving 
bent.  Is  it  a  "  unit  character,"  like  great  mathe- 
matical or  musical  ability,  or  can  the  illustrations 
of  it  be  analyzed  into  a  number  of  component 
factors,  such  as  curiosity,  pique,  dislike  of  hum- 
drum work,  antipathy  to  p'artkular  people,  un- 
willingness to  face  the  consequences  of  misdeeds, 
and  so  on?  It  appears  to  be  the  general  opinion  of 
alienists  that  there  are  quite  specific  "nomadic" 
sports  or  variations,  and  this  is  supported  by 
Dr.  Davenport's  evidence  of  the  recurrence  of 
"nomadic"  traits  generation  after  generation  in  a 
hundred  family  histories.  He  regards  nomadism  as 
probably  a  sex-linked  recessive  character.  "  Sons 
are  nomadic  only  when  their  mothers  belong  to  no- 
madic stock.  Daughters  are  nomadic  only  when 
the  mother  belongs  to  such  stock  and  the  father  is 
actually  nomadic.  When  both  parents  are  nomadic 


THE  ROVING  IMFULSE  193 

the  expectation  is  that  all  the  children  will  be."  As 
to  the  not  infrequent  concomitance  of  nomadism 
with  periodic  abnormal  psychoses,  such  as  de- 
pression or  hysteria,  Dr.  Davenport  thinks  that  this 
simply  means  that  these  abnormal  states  weaken 
or  paralyze  the  usual  inhibitions,  and  thus  allow 
the  nomadic  impulse  to  assert  itself.  He  is  con- 
vinced that  nomadism  is  a  perfectly  definite  herit- 
able character. 

The  second  question  is  whether  "  roving  "  is  a 
new  variation — a  germinal  experiment  so  to  speak, 
or  an  atavism  in  the  wide  sense — a  reversionary 
outcrop  of  an  antique  and  once  widespread  human 
instinct.  Or  it  may  be  that  there  are  two  types. 
Dr.  Davenport  regards  nomadism  rather  as  a 
negative  than  as  a  positive  trait,  holding  that  the 
characters  which  normally  make  for  steadiness 
and  settling-down  are  weak  or  absent,  with  the 
result  that  a  primitive  wandering  impulse  finds 
uninhibited  expression.  As  he  states  it,  in  modern 
phraseology,  "  the  nomadic  impulse  depends  upon 
the  absence  of  a  simple  sex-linked  gene  that  '  deter- 
mines '  domesticity  " — "  gene  "  meaning  a  "  unit- 
factor  "  or  particular  component  in  the  germinal 
inheritance.  On  this  view,  we  are  all  bearers  of  the 
vestiges  at  least  of  an  ancient  wandering  instinct 
supposed  to  be  primitive  in  mankind,  but  we 
normally  inhibit  or  regularize  its  development  or 
expression.  This  inhibition  comes  about  organi- 
cally, because  less  primitive  characters,  such  as 
having  and  loving  a  home,  are  stronger  than  the 


194          SECRETS  OF  ANIMAL  LIFE 

waning  nomadic  instincts.  It  also  comes  about: 
in  the  ordinary  course  of  social  discipline,  which 
soon  makes  us  feel  that  it  does  not  do  to  be  always 
running  away.  Dr.  Davenport  makes  the  interest- 
ing point  that  the  choice  of  an  occupation  often 
illustrates  an  attempt  to  satisfy  a  roving  impulse. 
Thus  the  antithesis  between  tinker  and  tailor  is 
familiar,  and  the  railway  guard  and  the  itinerant 
preacher  may  be  "  rovers "  in  disguise.  If  the 
assumption  be  correct  that  primitive  man  was 
nomadic  in  the  ordinary  sense  of  the  word,  a  prob- 
ability is  established  in  favor  of  Dr.  Davenport's 
view  that  a  wandering  tendency  is  still  widespread 
among  men  as  a  surviving  ancient  trait  which  now 
and  again  asserts  itself.  If  the  assumption  be 
correct,  gipsies,  and  others  like  them,  may  be  in- 
terpreted as  still  retaining  in  considerable  numbers 
the  old-fashioned  roaming  habit,  but  care  must  be 
taken  to  discriminate  if  possible  between  tribes  or 
groups  who  wander  because  they  will  and  those  who 
wander  because  they  must.  Some  may  have  be- 
come hunters  and  fishers  because  of  a  nomadic 
bent,  but  others  because  the  environmental  condi- 
tions did  not  admit  of  agriculture  or  stable  home- 
steads. The  way  in  which  the  East  Coast  herring 
fishermen  follow  for  more  than  half  the  year  the 
appearance  of  the  fish — the  undecided  question  as 
to  mass-movements  of  herring  need  not  be  raised — 
around  our  shores  is  a  modern  instance  of  roaming 
with  an  economic  rather  than  a  temperamental 
basis. 


THE  ROVING  IMPULSE  195 

It  is  interesting,  we  think,  to  inquire  whether 
there  may  not  be  two  kinds  of  nomadism.  It  may 
be  that  roving  manifestations  confined  to  early 
childhood,  or  to  adolescence,  or  associated  with 
marked  lack  of  control  and  grip,  are  due  to  the 
outcrop  of  an  ancestral  trait,  while  another  form 
expresses  an  independent  variation,  a  new  departure, 
an  organismal  experiment  in  the  direction  of  ex- 
ploration and  novelty-seeking.  It  is  marked  by 
great  power  of  control  and  by  resolute  resistance, 
though  it  sways  its  possessors  restlessly.  Perhaps 
many  of  the  great  explorers  and  naturalist-travelers 
illustrate  this  type,  men  who  cannot  rest,  as  Nansen 
once  said,  until  they  have  gone  through,  or  tried 
to  go  through,  every  room — even  the  ghost-room — 
of  the  vast  house  which  is  theirs. 

Dr.  Davenport  points  to  the  restless  habits  of 
the  gorilla  and  the  chimpanzee.  The  gorilla  family 
roams  about  in  search  of  food,  and  will  rarely 
stay  a  couple  of  nights  in  the  same  shelter.  We 
read  that  the  chimpanzee  never  uses  its  sleeping 
platform  a  second  night.  Now  it  may  be  that  the 
group  of  animals  to  which  the  ancestors  of  man 
belonged  were  typical  nomads,  but  there  seems  great 
risk  of  fallacy  when  nomadism  in  man  is  likened  to 
wandering  that  has  a  direct  relation  to  food-getting 
or  to  periodic  environmental  changes.  The  wander- 
jng  may  have  been  initiated  by  variants  akin  to 
roving  boys  in  mankind,  but  the  impulse  has  been 
tamed  and  incorporated  into  the  general  inheri- 
tance of  the  species  in  question,  and  may  be  ex-, 


196          SECRETS  OF  ANIMAL  LIFE 

hibited  by  types  which  have,  so  far  as  we  can  judge, 
very  little  of  the  roving  spirit  in  their  composition. 
We  are  far  from  saying  that  there  are  not  tempera- 
mental rovers  among  animals.  The  common  crab 
has  been  known  to  journey  along  the  sea-floor 
for  about  a  hundred  miles,  and  a  cod  may  take  a 
jaunt  of  several  hundreds,  but  our  point  is  that 
wanderings  like  those  of  locusts  and  lemmings, 
badly  called  migrations,  are  reactions  to  lack  of 
food.  We  have  admitted  the  probability  that  there 
might  not  be  these  effective  racial  reactions  to-day, 
had  there  not  arisen  long  ago  variants  with  a  rest- 
less, experimental,  exploring,  roving  disposition, 
who  conquered  difficulties  by  circumventing  and 
evading  them,  who  went  on  a  journey,  discovering 
the  truth  of  solvitur  ambulando;  but  what  we  main- 
tain is  that  locusts  and  lemmings  are  not  "  rovers  " 
now.  In  the  same  way  we  cannot  accept  the 
American  biologist' s  suggestion  that  "  nomadism 
in  man  is  of  the  same  order  as  that  of  birds,"  for 
bird-migration  is  a  long-established,  smoothly- 
working,  regularized  alternation  between  the  feed- 
ing and  resting  of  the  winter  quarters  and  the 
breeding  and  nesting  of  the  summer  quarters.  It 
probably  began  in  individual  variations  or  muta- 
tions in  the  direction  of  "  roving,"  but  the  instinct 
has  been  established  and  perfected  in  definite  rela- 
tion to  the  actual  necessities  of  nutrition  and  repro- 
duction as  affected  by  seasonal  changes. 

It  is  important  not  to  think  of  the  human  "  rover  " 
as  necessarily  pathological,  for  whether  he  is  one  in 


THE  ROVING  IMPULSE  197 

whom  an  ancient  instinct  has  been  rehabilitated,  or 
one  who  has  been  born  with  a  novel  mind-body  pat- 
tern, there  are  possibilities  in  him  of  up-grade 
development.  Repression  may  make  a  criminal  of 
the  stowaway  who  might  have  been  a  great  explorer, 
a  poacher  of  one  who  might  have  been  a  naturalist- 
traveler,  or  a  "  rolling-stone "  of  one  who  might 
have  been  a  scholar-gipsy.  In  the  course  of  life, 
especially  after  experiences  like  those  of  the  Great 
War,  many  who  were  for  a  time  restless  may  settle 
down  enriched,  while  others  who  had  a  strong  dose 
of  the  "  gene  determining  domesticity  "  may  use- 
fully indulge  the  assertion  of  a  new  inclination  to 
rove.  What  we  venture  to  suggest  is  that  these 
things — especially  everything  that  shakes  us  from 
humdrum  and  what  Shakespeare  called  "  life-harm- 
ing heaviness" — may  be  made  to  work  together 
for  good. 


XXVI 

THE  PROBLEM  OF  PARASITISM 

ONE  of  the  perplexing  shadows  in  the  pleasant 
picture  of  animate  nature  is  the  frequency 
of  parasitism.  To  some  minds  it  appears  as  a  blot 
spoiling  the  whole  script.  But  without  denying 
that  there  is  some  warrant  for  practical,  aesthetic, 
and  ethical  recoil,  we  think  that  much  of  this  is  due 
to  lack  of  perspective.  Let  us  take  a  rapid  survey 
of  the  facts.  Thousands  of  living  creatures,  both 
plants  and  animals,  live  in  or  on  others,  bound 
up  with  them  in  a  brutally  direct  nutritive  depend- 
ence and  incapable  of  living  in  any  other  way. 
Uninvited  non-paying  boarders  they  are,  who 
make  their  hosts  no  return  for  the  hospitality 
enjoyed.  When  we  think  of  the  "  minor  horrors  of 
war,"  regarding  which  Dr.  Shipley  has  written  so 
admirably,  of  yard-long  tapeworms  and  plump 
maw-worms  in  their  inglorious  life  of  ease,  of  mites 
and  ticks  innumerable,  of  fish-lice  and  flukes,  of 
rusts  and  mildews  and  other  parasitic  fungi,  and 
so  on  down  to  the  microscopically  minute  bacilli 
and  trypanosomes,  we  are  appalled  at  the  number 
and  diversity  of  parasites.  It  is  some  relief  to  find 
that  no  backboned  animals  are  parasitic  unless  it 
be  the  hags  (Myxine)  which  sometimes  burrow 

196 


THE  PROBLEM  OF  PARASITISM      199 

into  the  fishes  caught  on  the  fishermen's  deep-sea 
lines.  There  are  no  parasites  among  Echinoderms 
and  few  among  Mollusks  and  Coelentera,  perhaps  in 
part  because  the  life  of  these  types  depends  so  much 
on  the  action  of  living  lashes  (cilia  or  flagella)  in  a 
fresh  medium.  Among  plants  most  of  the  parasitic 
forms  are  fungi,  and  there  are  very  few  among 
flowering  plants.  But  there  is  no  getting  away  from 
the  fact  that  parasitism  is  a  very  common  mode  of 
life.  One  of  the  European  oaks  harbors  no  fewer 
than  ninety  and  nine  different  kinds  of  gall-flies, 
and  the  hundredth  will  probably  have  been  dis- 
covered before  this  series  of  studies  is  published. 
The  valuable  Lac  insect  of  India  is  beset  by  over 
thirty  animal  and  vegetable  parasites.  The  dog 
is  a  terrain  for  over  forty;  man  and  pig  have 
far  more.  In  short,  no  creature  with  a  body  is 
without  a  parasite,  and  the  number  that  may  pos- 
sess a  lusty  host  with  a  wide  range  of  appetite  is 
legion. 

The  association  between  parasite  and  host  is  often 
very  specific;  thus  the  larvae  of  some  of  the  fresh- 
water mussels  become  temporary  parasites  on 
particular  species  of  fishes  and  on  no  others,  and 
the  larva  of  the  liver-fluke  does  not  develop  in 
Britain  except  within  one  particular  kind  of  fresh- 
water snail.  The  relation  of  dependence — always 
nutritive,  and  often  more — between  parasite  and 
host  varies  greatly  in  intimacy,  for  there  are  ex- 
ternal hangers-on,  like  fish-lice,  and  intimate 
endoparasites,  which  become  almost  part  of  their 


200  SECRETS  OF  ANIMAL  LIFE 

host.  There  are  partial  parasites  which  spend  a 
chapter  or  two  of  their  life  in  freedom,  and  there 
are  complete  parasites  which  pass  from  host  to  host 
in  a  never-broken  vicious  circle.  In  proportion  to 
the  intimacy  of  the  dependence  is  the  degeneration 
of  the  parasite,  which  affects  especially  the  sensory, 
nervous,  muscular,  and  alimentary  systems.  The 
reproductive  system,  on  the  other  hand,  is  often 
highly  developed  and  the  multiplication  very  pro- 
lific. This  may  be  correlated  primarily  with  the 
abundance  of  stimulating  food  available  without 
exertion,  and  secondarily  with  the  enormous  chances 
of  death  in  the  life-history.  For  most  of  the 
parasites  owe  their  survival  to  being  many,  not  to 
being  strong.  The  intricacies  in  the  life-histories 
are  often  extraordinary,  and  are  due  in  part  to  the 
fact  that  the  parasite  has  to  share  in  the  knots  in 
which  their  hosts  are  involved  in  the  web  of  life, 
for  it  is  natural  enough  that  the  bladderworm  of 
the  mouse  should  become  the  tapeworm  of  the  cat. 
Ugly  parasites  are  common,  but  many  are  conspicu- 
ously well  adapted.  Thus  the  tapeworm  absorbs 
food  by  the  whole  surface  of  its  body;  it  is  fixed 
to  its  host  by  muscular  adhesive  suckers  and  often 
by  attaching  hooks  as  well;  it  can  thrive  with  a 
minimum  of  oxygen;  it  has  a  mysterious  "anti- 
body "  which  saves  it  from  being  digested  in  its 
host's  intestine;  it  produces  millions  of  eggs  which 
it  is  able  to  fertilize  of  itself.  It  may  be  repulsive, 
but  in  the  technical  biological  sense,  relative  to 
given  conditions,  it  is  "  fit." 


THE  PROBLEM  OF  PARASITISM      201 

The  repugnance  which  many  people  feel  when 
they  think  of  parasites  is  partly  practical.  They  re- 
sent the  fact  that  a  contemptible  microbe  kills  the 
genius  before  he  comes  of  age,  and  that  paltry  flies 
put  a  drag  on  the  wheel  of  the  chariot  of  civiliza- 
tion. But  this  is  a  one-sided  view.  Many  parasites 
do  little  harm  to  their  host;  a  modus  vivendi  has 
been  established.  The  thousands  of  Nematodes 
in  the  food-canal  of  a  grouse  seem  of  no  moment 
if  the  bird  be  healthy.  If  it  be  of  a  weakly  consti- 
tution, however,  the  parasites,  otherwise  trivial, 
may  gain  the  upper  hand  and  eliminate  their  host. 
As  this  sifting  makes  for  racial  health  it  cannot  be 
called  abhorrent.  The  effects  of  parasites  on  their 
hosts  are  extraordinarily  varied;  some  give  off 
toxic  substances;  others,  like  the  beautiful  Infu- 
sorians  in  a  horse's  stomach,  appear  to  be  to  some 
extent  helpful;  some  cause  internal  lesions,  and 
others  provoke  beautiful  imprisoning  growths  like 
the  oak-apples  in  the  wood  and  the  pearls  in  the 
oyster.  The  sturdie-worm  causes  locomotor  ataxia 
in  the  sheep  whose  brain  it  inhabits,  but  fish-lice 
seem  often  entirely  unimportant  to  their  bearers. 
Almost  every  earthworm  has  parasitic  Gregarines 
in  its  reproductive  organs,  but  they  are  not  usually 
of  moment;  on  the  other  hand,  the  parasitic 
Crustaceans  known  as  Rhizocephala  actually  destroy 
the  reproductive  organs  of  crabs.  More  than  that, 
they  change  the  constitution  of  the  male  towards 
the  female  type,  so  that  a  small  ovary  sometimes 
develops;  the  shape  of  the  abdomen  approximates 


202          SECRETS  OF  ANIMAL  LIFE 

to  that  of  the  female,  and  the  protruding  parasite 
is  actually  guarded  by  its  bearer  as  if  it  were  a 
bunch  of  eggs.  On  the  other  hand,  many  external 
parasites  behave  as  if  their  end  in  life  was  to  do  for 
their  host  what  he  will  not  do  for  himself,  namely, 
keep  his  skin  clean.  Great  mortality  from  parasites 
is  in  most  cases  due  to  immigrant  animals  entering 
a  fresh  area  and  becoming  liable  to  attack  by  para- 
sites to  which  they  can  offer  no  natural  resistance, 
as  when  cattle  enter  the  Tse-tse  fly  belt  and  become 
infected  with  trypanosomes  which  are  fatal  to  them, 
though  doing  little  or  no  damage  to  the  indigenous 
animals  in  which  they  are  at  home.  Similarly,  the 
fatality  of  a  new  parasite  in  a  new  population  is 
familiar,  as  in  the  case  of  the  Black  Death  in  Eng- 
land, which  was  due  to  the  introduction  of  the 
microbe  of  bubonic  plague  from  the  East.  It  is  not 
the  parasite's  interest  to  kill  its  host — that  is  killing 
the  goose  that  lays  the  golden  eggs — but  it  is  highly 
probable  that  very  aggressive  parasites  have  elimi- 
nated themselves  from  time  to  time  by  turning 
into  beasts  of  prey.  For  it  seems  almost  legitimate 
to  place  by  themselves,  and  outside  the  ranks  of 
ordinary  parasites,  the  very  virulent  microbes  like 
Plague  Bacilli  and  Sleeping-Sickness  Trypanosomes. 
They  are  internal  plants-of-prey  and  beasts-of-prey, 
and  it  is  interesting  to  notice  that  some  of  them 
live  an  exceedingly  active  life,  which  is  not  the  usual 
habit  of  adult  parasites. 

Many  parasites  are  aesthetically  repulsive  in  form, 
color,   and  movements,   and  it  is  instructive  to 


THE  PROBLEM  OF  PARASITISM     203 

compare  the  attractive  free  stages  of  some  of  them 
with  the  ungraceful,  bloated,  absorbent  masses  of 
tissue  which  they  may  become  as  adults.  The  ugli- 
ness is  Nature's  stamp  of  degeneracy  and  dishonor; 
it  is  the  natural  result  of  retrogression,  involution, 
sluggishness,  and  overfeeding.  Beauty  is  universal 
among  free-living,  full-grown,  wild  creatures  in  a 
state  of  health  and  away  from  man's  fingers;  ugli- 
ness is  the  brand  of  failure.  As  George  Meredith 
said :  "  Ugliness  is  only  half-way  to  a  thing."  It 
is  interesting  to  notice  that  the  dodder  and  mistletoe, 
which  every  one  recognizes  as  beautiful,  are  only 
partial  parasites.  Inextricably  associated  with  the 
purely  aesthetic  repugnance  is  the  feeling  that  an 
organism  which  does  not  fend  for  itself  is  a  sort  of 
contradiction  in  terms. 

To  many  minds,  indeed,  the  darkness  of  the 
shadow  is  in  the  inconsistency  between  the  parasitic 
regime  and  Nature's  usual  insistence  on  a  strenu- 
ous life.  This  must  be  admitted,  and  yet  there  are 
extenuating  circumstances.  In  the  struggle  for 
existence  the  organism  finds  itself  beset  by  environ- 
ing difficulties  and  limitations,  and  one  of  the  re- 
actions that  sometimes  pay  is  to  become  a  parasite. 
But  the  struggling  creature  does  not  see  it  in  our 
light,  and  has  no  prevision  of  the  facilis  descensus 
on  which  it  sets  foot.  It  may  try  to  survive  inside 
a  larger  organism  which  has  swallowed  it,  just  as 
another  may  try  to  survive  in  a  cave,  and  another 
in  a  warm  spring.  In  its  searching  for  food  and 
shelter  it  may  discover  in  or  on  another  organism 


204          SECRETS  OF  ANIMAL  LIFE 

what  is  for  it  simply  a  new  and  very  promise ful 
world.  In  many  cases  it  is  only  the  mother-animal 
that  is  parasitic,  so  that  it  is  not  necessarily  a  selfish 
evasion  of  struggle  this  parasitism.  It  is  not  easy 
to  fence  off  parasites  that  may  be  of  a  little  benefit 
to  their  hosts  from  symbions  and  commensals 
that  are,  on  the  whole,  beneficial,  but  levy  a  slight 
tax.  All  these  linkages  are  to  be  looked  at  broadly 
as  expressions  of  a  widespread  tendency  to  weave 
lives  together  in  a  web — an  external  systematiza- 
tion  or  correlation  which  has  been  of  great  moment 
in  evolution. 

Some  have  explained  that  it  is  not  the  destruc- 
tiveness  of  parasites  that  they  object  to,  nor  their 
ugliness,  nor  even  their  feckless,  drifting  life,  but  a 
certain  element  of  devilry.  The  ichneumon-fly 
lays  her  eggs  in  a  caterpillar;  the  hatched  grubs 
feed  on  the  living  tissues;  they  make  their  way  out 
eventually  to  begin  a  new  phase  of  life,  having 
killed  their  host  It  is  very  difficult  in  such  cases 
to  avoid  anthropomorphism.  Perhaps  it  does  not 
matter  much  to  the  caterpillar  whether  it  is  devoured 
from  the  inside  or  from  the  outside,  and  perhaps  the 
ichneumon  larvse  are  rather  beasts  of  prey  than 
parasites.  This,  at  least,  is  certain — that  what  the 
ichneumon  insect  does  to  the  caterpillar  is  not  so 
repulsive  as  what  man  often  does  to  man,  for  man 
knows  or  ought  to  know  what  he  is  doing.  The 
devilry,  indeed,  is  all,  unfortunately,  with  the  man, 
for  the  icheumon's  behavior  is  the  expression 
not  so  much  of  devilry  as  of  a  certain  "  wildness  " 


THE  PROBLEM  OF  PARASITISM      205 

that  often  crops  out  in  Nature.  No  explanation 
can  be  offered  except  that  organisms,  even  plants, 
have  in  them  something  akin  to  the  artist's  genius. 
They  have  great  resources,  they  are  creative,  and 
they  are  free. 


XXVII 
WONDERS  OF  INSTINCT 

FEW  men  have  had  a  better  right  to  speak 
about  instinct  than  Henri  Fabre,  whom 
Darwin  in  The  Origin  of  Species  spoke  of  as  "  that 
inimitable  observer,"  for  his  genius  in  scrutiny  as 
well  as  in  sympathy  brought  him  into  unusually 
close  acquaintance  with  the  life  of  insects  where 
instinctive  behavior  reaches  its  climax.  For 
whatever  be  our  theory  of  instinct,  there  is  no 
doubt  that  it  is  seen  in  its  purest  and  most  perfect 
expression  in  those  creatures  which  belong  to  what 
Sfr  Ray  Lankester  calls  the  "little-brain"  type. 
When  we  pass  from  ants,  bees,  and  wasps  to  the 
big-brained  birds  we  feel  at  once  a  change  of  air; 
inference  and  learning  are  at  work  as  well  as  the 
inborn  inspirations  of  instinct.  The  appearance  of 
a  collection  of  Fab  re's  essays  under  the  title  The 
Wonders  of  Instinct  has  brought  us  again  to  face 
the  old  puzzle:  What  is  the  nature  of  instinctive 
behavior?  But  let  us  first  ask  the  humbler  ques- 
tion: In  what  particular  ways  is  instinct  wonderful, 
where  all  is  wonderful  ? 

The  first  marvel  that  the  great  naturalist's  dis- 
closures   suggest   is    the    extraordinary   perfection 

1  Fisher  Unwin.    IDS.  6d.  net. 
206 


WONDERS  OF  INSTINCT  207 

which  instinctive  behavior  often  exhibits.  The 
solitary  wasp  called  Eumenes  amedei  attains  great 
excellence  alike  in  the  chase  and  in  the  craft  of 
building;  it  is  "  a  Nimrod  and  a  Vitruvius  by 
turns."  With  minute  pebbles  and  salivated  mortar 
it  builds  a  finely-finished  cupola  about  three- 
quarters  of  an  inch  in  height;  the  outside  is  covered 
with  glistening  grains  of  quartz  or  sometimes  with 
tiny  snail  shells;  the  orifice  at  the  top  is  "like  the 
mouth  of  an  amphora,  gracefully  curved,  worthy 
of  a  potter's  wheel."  After  the  mother  wasp  has 
placed  an  egg  in  her  well- fashioned  nest,  she  adds 
five  to  ten  small  caterpillars,  and  it  is  remarkable 
that  the  egg  in  the  well-stocked  nest  develops  into 
a  female  wasp,  while  that  in  the  meagerly  pro- 
visioned nest  becomes  the  much  smaller  male.  It 
may  be  that  the  difference  in  the  nutritive  supply 
determines  the  forthcoming  sex,  giving  a  con- 
stitutional bias  to  one  side  or  the  other,  for 
Fabre  was  surely  off  the  track  in  supposing  that 
"the  mother  knows  beforehand  the  sex  of  the  egg 
she  is  about  to  lay,"  and  has  "  a  clear  vision  of  the 
invisible."  But  to  return  to  the  nest,  after  egg- 
laying  and  victualing,  the  next  step  is  to  close  the 
orifice  with  a  cement  plug,  in  which  there  is  always 
set  a  single  tiny  pebble.  "  The  ritual  never  varies." 
But  the  touch  of  perfection  is  to  be  found  inside, 
not  outside.  It  appears  that  the  stung  caterpillars 
that  form  the  living  larder  inside  the  wasp's  cell 
are  but  imperfectly  paralyzed,  and  toss  about  when 
touched.  Now  the  least  pressure  would  crush  the 


208          SECRETS  OF  ANIMAL  LIFE 

delicate  egg.  So  it  is  hung  by  a  thread  from  the 
roof  of  the  cupola,  and  after  the  Eumenes  grub 
hatches,  it  makes  the  cast  shell  of  the  egg  into  a 
flexible  staircase  so  that  it  can  reach  the  caterpillars 
and  bite  them,  yet  retreat  if  they  are  too  vigorously 
recalcitrant.  This  is  perfection. 

The  second  point  which  Fabre's  observations 
illustrate  very  finely  is  the  frequently  serial  char- 
acter of  instinctive  behavior.  There  is  a  particular 
sequence,  and  that  sequence  is  adaptive.  The 
Capricorn  grub  of  the  Cerambyx  beetle  burrows  for 
three  years  on  end  in  the  depths  of  an  oak  tree. 
But  when  it  is  full-grown  and  the  time  of  its  meta- 
morphosis draws  near,  it  moves  to  the  periphery 
and  makes  a  passage  almost  out,  leaving  only  a 
film-like  screen,  just  as  if  it  knew  that  the  winged 
beetle  to  emerge  from  the  pupa-case  would  other- 
wise be  buried  alive.  It  then  draws  back  a  little 
in  its  gallery  and  makes  an  outer  barricade  of 
particles  of  chopped  wood,  and  inside  that  an 
inner  partition  like  a  white  skull-cap  or  acorn-cup, 
composed,  strange  to  say,  of  carbonate  of  lime  and 
some  organic  cement.  The  next  step  is  to  make 
on  the  side  of  the  exit-way  a  transformation- 
chamber.  This  is  three  or  four  inches  long,  and  is 
padded  "  with  a  fine  swan's  down,  a  delicate  pre- 
caution taken  by  the  rough  worm  on  behalf  of  the 
tender  pupa."  The  next  step  is  to  fall  asleep  and 
dream  of  becoming  a  beetle.  :c  The  grub  lays  asiuo 
its  tools,  molts  its  cuticle  and  becomes  a  pupa, 
lying,  weakness  personified,  on  a  soft  couch.  The 


WONDERS  OF  INSTINCT  209 

head  is  always  turned  towards  the  door.'*  This 
seems  a  minute  detail,  but  the  strength  of  a  chain 
is  that  of  its  weakest  link.  The  supple  grub  can 
turn  this  way  or  that  in  its  chamber,  but  the  coming 
Cerambyx  will  not  be  able  to  turn  or  bend.  "  He 
.must  absolutely  find  the  door  in  front  of  him,  lest 
he  perish  in  the  casket.  Should  the  grub  forget  this 
little  formality,  should  it  lie  down  to  its  nymphal 
sleep  with  its  head  at  the  back  of  the  cell,  the  Cap- 
ricorn is  infallibly  lost;  his  cradle  becomes  a  hopeless 
dungeon."  But  the  grub  forgets  as  little  as  it 
learns ! 

The  third  feature  which  Fabre's  studies  bring 
into  prominence  is  the  limitation  of  instinct.  Often 
subtle  and  perfect,  without  a  loose  thread  from 
first  to  last,  the  instinctive  routine  often  ends  in 
an  almost  ridiculous  fiasco,  when  a  grain  of  in- 
telligence would  have  saved  the  situation.  The 
fact  is,  of  course,  that  the  instinctive  capacity  has 
been  slowly  and  exquisitely  adapted  for  the  ninety- 
nine  per  cent,  of  normal  circumstances,  not  to  meet 
the  one  per  cent,  of  exceptional  contretemps. 
Strange  it  is,  however,  that  the  burying  beetles  will 
allow  themselves  to  pine  away  in  an  artificial  prison 
which  has  for  such  expert  tunnel-makers  a  widely- 
open  door — widely  open  physically,  but  closed 
psychically.  They  often  show  great  pertinacity  in 
trying  to  bury  a  mouse  in  difficult  conditions,  but 
Fabre's  ingenious  experiments  showed  that  they 
were  baffled  by  simple  tricks  of  suspension  where  a 
touch  in  the  right  direction  would  have  made  the 


210  SECRETS  OF  ANIMAL  LIFE 

booty  available.  The  observer  once  made,  as  is 
well  known,  a  closed  circuit  of  procession-cater- 
pillars on  the  rim  of  a  palm-vase  in  his  garden,  and 
round  this  on  a  silken  trail  the  creatures  continued 
crawling  in  futile  circumambulation  for  seven  times 
twenty-four  hours,  working  round  and  round  three 
hundred  and  thirty-five  times  and  covering  a 
distance  of  a  good  bit  over  a  quarter  of  a  mile.  This 
and  a  score  of  similar  cases  illustrate  what  Fabre 
calls  "  the  abysmal  stupidity  "  of  insects  whenever 
the  least  accident  occurs.  We  should  rather  say 
the  tyranny  of  instinctive  impulse  in  artificial  or 
quite  unusual  circumstances.  "  The  caterpillars 
in  distress,  starved,  shelterless,  chilled  with  cold  at 
night,  cling  obstinately  to  the  silk  ribbon  covered 
hundreds  of  times,  because  they  lack  the  rudi- 
mentary glimmers  of  reason  which  would  advise 
them  to  abandon  it."  We  should  rather  say 
because  the  hand  of  the  past  in  the  form  of  a  routine 
of  response  enregistered  in  the  nervous  system  was 
too  strong  to  allow  of  any  initiative  in  the  present. 
To  what  theory  do  these  interesting  facts  point? 
It  seems  to  us  that  Bergson  was  right  in  insisting 
that  instinctive  behavior  is  on  a  different  evolu- 
tionary tack  from  intelligent  behavior.  The  latter 
is  inferential  and  reflective;  the  former  is  impulsive 
and  intuitive.  Intelligence  implies  an  appreciation 
of  relations;  instinct  implies  an  appreciation  of  a 
particular  configuration  of  circumstances.  In- 
telligence is  as  much  made  as  born;  instinctive 
capacity  is  much  more  inborn  than  made.  In  the 


WONDERS  OF  INSTINCT  211 

course  of  ages  the  fountain  of  change  in  the  germ- 
cells  has  supplied  material  for  cumulative  improve- 
ments in  structure,  in  the  creature's  instruments. 
In  the  course  of  ages  the  same  fountain  has  supplied 
material  for  cumulative  improvements  in  the 
controlling  organization,  the  nervous  system,  objec- 
tively regarded,  the  mental  life  subjectively  regarded. 
The  correlation  of  improved  control  and  improved 
instruments  is  effected  in  the  slow  winnowing  of 
Natural  Selection,  which  always  operates  in  definite 
reference  to  a  particular  set  of  often-recurrent  or 
absolutely  critical  external  circumstances.  These, 
in  turn,  may  gradually  become  more  intricate  and 
subtle,  and  thus  act  as  an  evolving  sieve.  We 
agree  with  those  who  find  it  difficult  to  think  over 
a  complicated  case  of  instinctive  routine  without 
the  hypothesis  that  it  is  suffused  with  some  degree 
of  awareness  and  sustained  by  some  degree  of 
endeavor.  We  find  no  warrant  for  regarding 
instinct  as  a  sort  of  low-grade  intelligence,  still 
less  as  the  result  of  lapsed  intelligence.  We  think 
Fabre  was  nearer  the  truth  with  his  phrase  "  inborn 
inspiration,"  and  that  we  make  difficulties  for  our- 
selves by  trying  to  give  purely  physiological  explana- 
tions of  what  is,  like  memory,  a  more  than  physio- 
logical phenomenon.  It  seems  to  have  been  part 
of  the  tactics  of  Nature  to  enregister  capacity  in 
the  organism  so  as  to  give  it  greater  freedom  for 
fresh  adventure.  In  the  case  of  instinctive  capacity, 
which  gives  the  creature  a  rapid  mastery  of  intricate 
situations,  the  enregistration  has  sometimes  outshot 


212  SECRETS  OF  ANIMAL  LIFE 

the  mark,  and  for  lack  of  a  little  logic  the  creature 
is  often  fatally  nonplussed.  But  in  the  big-brained 
type,  with  its  rapid  educability  and  capacity  for 
profiting  by  experience,  there  is  likewise  liability  to 
failure,  and  very  notably  in  mankind,  for  lack  of 
more  instinctive  wisdom.  On  the  whole,  however, 
intelligence  is  the  more  excellent  way,  especially 
when  external  registration  in  a  social  heritage  is 
added  thereto. 


XXVIII 
MAKING   A   HOME   FOR  LIFE 

WHETHER  the  earth  condensed  from  a 
whirling  ring  separated  off  from  a  spinning 
nebular  mass,  whose  center  formed  our  sun,  or 
whether  it  began  its  separate  existence  as  a  knot  in 
a  spiral  nebula  heaved  off  from  the  sun,  or  whether 
its  origin  was  otherwise,  there  was  a  time  when  it 
passed  from  being  "  without  form  and  void "  to 
become  a  dense  body  with  a  predominantly  metallic 
core  and  an  outer  slag  of  lighter  materials.  At 
that  time,  preferably  left  undated,  but  many 
millions  of  years  ago,  the  high  temperature  excluded 
the  possibility  of  there  being  upon  the  earth  any- 
thing like  the  living  organisms  we  know.  The  time 
for  life  was  not  yet,  and  what  we  wish  to  think  over 
are  some  of  the  preparations  (if  the  word,  not  quite 
scientific,  we  fear,  be  permissible)  that  made  the 
earth  fit  to  be,  if  not  mother  of,  in  any  case  a 
home  for,  living  creatures.  When  these  eventually 
came  to  their  own,  many  of  them  acquired  a  con- 
siderable toughness,  and  some  a  capacity  for  in- 
surgence,  but  the  present-day  delicacy  of  individual 
beginnings,  the  tenuity  of  the  germ,  the  helplessness 
of  the  infant,  remind  us  of  the  probable  frailty  of 
the  earliest  forms  of  life.  It  is  interesting  to 

213 


214  SECRETS  OF  ANIMAL  LIFE 

inquire  how  the  callous,  rough-and-tumble  condi- 
tions of  the  outer  world  allowed  of  the  germination 
and  growth  of  that  tender  plant  which  we  call  life. 
In  this  inquiry  we  shall  chiefly  follow  the  con- 
siderations recently  brought  forward  by  Professor 
Chamberlin  in  his  Origin  of  the  Earth  (Chicago 
University  Press,  1916),  and  by  Professor  Hender- 
son in  his  Order  of  Nature  (Harvard  University 
Press,  1917). 

Around  the  young  earth,  more  or  less  cooled 
down,  there  was  wrapped  an  atmosphere,  laden  with 
"  planetesimal  "  dust  which  sank  gently  on  to  the 
surface  and  drifted  about  in  billowy,  changeful 
dunes.  By  its  early  "ultra-Krakatoan "  atmo- 
sphere, as  Professor  Chamberlin  calls  it,  "  the 
young  earth  was  blanketed  against  intensities  of 
radiance  from  without  "  (a  younger,  more  intensely 
radiant  sun)  "and  inequalities  of  radiance  from 
within/'  This  "  preparation "  afforded  by  the 
atmosphere  was  probably  of  great  importance, 
for  the  average  living  creature,  as  we  know  it,  is 
adapted  to  mild  temperatures  and  gentle  reactions 
and  ill  suited  for  violent  vicissitudes.  Time  passed, 
and  from  the  growing  atmosphere  water  condensed 
on  the  surface  of  the  earth,  and  was  gradually 
absorbed  by  the  porous,  dusty  mantle,  till  by  and 
by  in  the  hollows  among  the  dunes  there  appeared 
pools  and  lakelets,  from  which  grew  lakes  and  seas. 
To  an  atmosphere  was  added  a  second  "prepara- 
tion/' a  hydrosphere,  and  that  brought  the  possi- 
bility of  life  nearer. 


MAKING  A  HOME  FOR  LIFE          215 

For,  without  going  very  deeply  into  the  subject, 
it  is  clear  that  water  was  a  precursor  of  life,  just  as 
it  now  is  an  essential  concomitant  of  all  vital 
activity.  Professor  Henderson  has  worked  out  its 
appreciation.  "  Water  can  dissolve  a  larger  variety 
of  substances  in  greater  concentration  than  any 
other  liquid";  "an  enormous  quantity  of  heat  is 
necessary  in  order  completely  to  evaporate  away  a 
lake  or  pond,  and  a  smaller,  but  still  very  large, 
quantity  must  be  given  off  before  such  a  body  of 
water  can  freeze  throughout  its  whole  extent"; 
the  well-known  anomalous  expansion  of  fresh  water 
near  the  freezing-point  conserves  liquid  water  and 
the  life  in  it.  And  what  shall  we  say  of  its  capacity 
for  hydrolytic  cleavage,  or  of  the  mobility  of  its 
molecules,  so  important  in  bodily  functions? 

But  just  as  water  necessarily  appeared  upon  the 
earth  when  the  times  were  ripe,  so  carbon  dioxide 
was  as  necessarily  present  as  a  primary  constituent 
in  the  air,  and  the  relations  of  the  two  made  for 
progress.  For  the  law  of  the  solubility  of  carbon 
dioxide  in  water  is  such  that  at  temperatures  con- 
sistent with  the  presence  of  a  hydrosphere  "  it  must 
always  be  somewhat  evenly  distributed  between 
the  air  and  the  waters  of  the  globe.  Water  can 
never  wash  the  carbonic  acid  out  of  the  air,  nor  the 
extract  it  from  the  water."  Moreover,  the  pres- 
ence of  carbonic  acid  in  the  rain  enabled  the  waters 
of  the  earth  to  mobilize  in  moderation  the  resources 
locked  up  in  minerals. 

The  origin  of  living  organisms  upon  the  earth 


216          SECRETS  OF  ANIMAL  LIFE 

remains  an  unread  riddle;  but,  in  spite  of  admittedly 
great  difficulties,  many  evolutionists  incline  to  the 
theory  that  very  simple  living  creatures  may  have 
arisen  from  so-called  inanimate  materials  as  the 
outcome  of  natural  synthetic  processes.  If  this  be 
so,  a  new  significance  appears  in  the  abundance  of 
carbon,  hydrogen,  and  oxygen  on  the  surface  of  the 
juvenile  earth,  and  in  what  the  chemists  tell  us  of 
the  unique  ensemble  of  properties  possessed  by 
these  three  wonderful  elements.  They  have  great 
reactivity;  they  make  great  diversity  possible; 
they  make  for  concentrations  and  complexifica- 
tions,  and  these  again  favor  the  formation  of 
colloidal  systems.  Now,  all  living  creatures  are 
essentially  built  up  of  proteins  and  other  carbon 
compounds  in  a  colloidal  state.  Only  in  that  state 
could  materials  have  the  pliancy  and  the  per- 
meability which  are  characteristic  of  organisms, 
and  that  "  energia "  of  which  Thomas  Graham 
wrote  in  1861  that  it  "  may  be  looked  upon  as  the 
probably  primary  source  of  the  force  appearing  in 
the  phenomena  of  vitality/'  Now,  while  almost 
all  substances  can  be  made  to  assume  the  hetero- 
geneous colloidal  state,  with  ultra-microscopic 
particles  or  droplets  in  suspension  or  dispersion  in 
some  medium,  there  is  a  notable  readiness  on  the 
part  of  complex  chemical  substances  to  pass  into 
that  "dynamical  state,"  as  Graham  called  it.  But, 
as  Professor  Henderson  reminds  us,  "  of  all  the 
chemical  elements,  hydrogen,  carbon,  and  oxygen 
possess  the  greatest  number  of  compounds  and 


MAKING  A  HOME  FOR  LIFE         217 

enter  into  the  greatest  number  of  reactions/'  !<  The 
unique  properties  of  hydrogen,  carbon,  and  oxygen, 
of  water  and  carbon  dioxide,  are  uniquely  favor- 
able to  the  existence  of  the  greatest  possible 
number,  variety  and  quantity  of  components  of 
systems." 

Along  with  the  special  properties  of  carbon, 
hydrogen,  and  oxygen,  we  must  think  of  their  very 
wide  distribution,  which  again  may  be  associated 
causally,  as  Mendeleeff  indicated,  with  their  small 
atomic  weights.1  Continuing  our  story,  we  see  the 
interest  of  an  idea  which  Professor  Chamberlin 
suggests,  that  the  pores  of  the  growing  soil  might 
afford  "  an  adequate  mechanism  for  holding, 
protecting,  and  preserving  the  products  of  each 
successive  step  in  such  a  way  as  to  favor  the  next 
synthetic  step."  And  whether  "  spontaneous  gene- 
ration "  took  place  in  the  pores  of  the  soil,  or 
whether  the  appearance  of  living  organisms  was  due 
to  factors  which  remain  outside  the  scientific  uni- 
verse of  discourse,  it  is  certain  that  the  natural 
conditions  were  propitious.  Thus  the  soil  supplies 
a  sort  of  circulatory  mechanism  for  bringing  in 
supplies  and  carrying  away  waste.  There  is  an  intri- 
cate canal  system  of  capillary  spaces  and  air-ducts  in 
the  soil.  Nothing  could  be  better  for  the  young 
forms  of  life,  however  these  arose. 

Of  incalculable  importance  has  been  throughout 
the  ages  the  persistent  circulation  of  matter,  and 
the  meteorological  cycle  in  particular.  Water 
better  to  New  Statesman,  June  8,  1918,  p.  191. 


218  SECRETS  OF  ANIMAL  LIFE 

condenses  from  the  atmosphere,  percolates  through 
the  soil,  with  the  help  of  the  associated  carbon 
dioxide  dissolves  mineral  matter,  flows  to  the  sea, 
and  rises  again  in  cloud.  Thus  it  regulates  the 
temperature  of  land  and  sea,  mobilizes  and  dis- 
perses large  quantities  of  elements,  gives  the  sea 
an  approximate  constancy  of  composition,  canalizes 
the  earth,  produces  great  terrestrial  diversity,  and 
so  on.  So  from  Professor  Henderson's  panegyric 
on  water  as  a  factor  in  evolution  we  pass  naturally 
to  Professor  Chamberlin's  emphasis  on  the  relative 
uniformity  which  the  meteorological  cycle  and 
other  processes  have  ensured.  "  Perhaps  there  is  no 
fact  in  the  earth's  career  more  remarkable  than  the 
fidelity  with  which  the  very  narrow  ranges  of 
temperature,  and  the  not  less  narrow  ranges  of 
atmospheric  constituents  essential  to  the  evolution 
of  life,  have  been  maintained,  while  oscillations 
within  these  permissible  ranges  have  freely  pre- 
vailed. These  limits  and  these  oscillations  were 
perhaps  as  imperative  for  life's  origin  as  for  its 
prolonged  maintenance."  The  steadiness  of  the 
physico-chemical  environment,  which  has  been 
friendly  to  the  ascent  of  life,  is  not  inconsistent 
with  there  being  a  gradual  change  in  soil  and  in 
climate  which  may  have  served  as  a  spur  to  the 
evolution  of  organisms.  Organic  evolution  has  had 
its  pulse,  responding  to  ameliorating  or  depress- 
ing external  conditions,  just  as  our  individual  pulse 
responds  to  a  sunny  or  a  gloomy  day.  "  Does  not 
a  man,"  John  Burroughs  said,  "  imply  a  cooler 


MAKING  A  HOME  FOR  LIFE          219 

planet  and  a  greater  depth  and  refinement  of  soil 
than  a  dinosaur?  " 

The  old  lady  saw  providential  design  in  the  way 
so  many  fine  rivers  flowed  through  so  many  large 
towns.  Are  we  making  the  same  sort  of  mistake 
in  discerning  that  the  constitution  of  the  inanimate 
is  in  many  unique  ways  eminently  favorable  to 
the  interests  of  living  creatures?  If  it  be  true 
that  primitive  living  creatures  arose  by  processes 
of  natural  synthesis  upon  the  earth,  and  are  in  a 
deep  sense  bone  of  her  bone  and  flesh  of  her  flesh, 
it  is  not  surprising  that  the  mother  should  be 
friendly  to  her  children.  One  would  expect  systems 
thus  arising  to  be,  as  it  were,  at  home  among  the 
conditions  which  gave  them  birth.  But  what 
strikes  one  is  that  the  callous  earth  has  been  so 
conspicuously  friendly,  supplying  not  merely  a 
shelter,  but  a  stimulating  and  educative  home. 
Such  a  multitude  of  "  preparations "  seem  to 
conspire  together  to  facilitate  life — the  making  of 
the  atmosphere  and  hydrosphere,  the  properties  of 
water  and  carbonic  acid  gas  separately  and  together, 
the  properties  and  abundance  of  carbon,  hydrogen, 
and  oxygen,  the  ready  assumption  of  a  colloidal 
state  by  complex  carbon  compounds,  the  character 
of  the  porous  soil,  and  the  meteorological  cycle. 
The  whole  aspect  of  life  would  have  been  different 
if  fresh  water  had  not  the  anomalous  property  of 
expanding  near  the  freezing-point,  just  as  the  whole 
aspect  of  human  history  would  have  been  different 
if  our  atmosphere  had  been  too  cloudy  to  allow  us 


280          SECRETS  OF  ANIMAL  LIFE 

to  see  the  stars.  It  is  easy  to  assert  that  with  other 
elements,  with  other  properties,  there  might  have 
been  other  living  creatures,  very  different  from  those 
we  know,  yet  just  as  well  adapted  and  just  as 
marvelous  and  beautiful;  but  no  one  has  substan- 
tiated this  assertion.  The  fact  to  stand  firm  on  is 
that  the  order  of  inanimate  Nature  has  been  such 
that  it  facilitated  the  order  and  progress  of  animate 
Nature.  The  "  material  nature  " — the  stones  and 
mortar  of  the  world — must  be  admitted  to  have 
had  a  character  which  made  the  preparation  of  a 
home  for  life  possible — a  potentiality  to  which  we 
do  not  seem  to  do  anything  like  full  justice  unless 
we  call  it  purposive.  But  preparing  a  home  for  life 
was  not  all,  for  far  in  the  future  there  was  the 
rational  mind  of  man,  prying  into  the  facts,  puzzling 
over  them,  in  part  understanding  them;  and  if  this 
also  evolved  naturally,  there  is  no  way,  even  if  we 
wished,  of  escaping  the  conclusion  that  what  we 
call  material  is  also  spiritual,  for  there  can  be 
nothing  in  the  end  which  was  not  also  present  in 
kind  in  the  beginning.  It  looks,  then,  as  if  Nature 
was  Nature  for  a  purpose. 


XXIX 
WITH  DARWIN  FORWARDS 

IT  is  difficult  not  to  sympathize  with  the  idea 
that  there  must  be  some  hereditary  entail- 
ment  of  at  least  a  representation  of  many  of  the 
individual  gains  made  by  living  creatures  during 
their  lifetime.  It  is  difficult  to  shut  out  the  belief 
that  individual  experience  must  somehow  count  in 
racial  evolution.  Thus  it  is  not  surprising  that  we 
should  often  hear  the  slogan  "  Back  to  Lamarck !  " , 
The  importance  of  the  questions  raised  is  so  great 
that  no  apology  is  needed  for  an  attempt  to  suggest, 
the  other  side  of  the  case.  We  must  remember 
Herbert  Spencer's  conviction,  that  "  a  right  answer 
to  the  question  whether  acquired  characters  are  or 
are  not  inherited  underlies  right  beliefs,  not  only  in 
Biology  and  Psychology,  bat  also  in  Education, 
Ethics,  and  Politics.  ...  A  grave  responsibility 
rests  on  biologists  in  respect  of  the  general  question, 
since  wrong  answers  lead,  among  other  effects,  to 
wrong  belief  about  social  affairs,  and  to  disastrous 
social  actions."  These  words  should  remove  all 
trace  of  polemical  argumentation  from  our  inquiry. 
The  central  question  is  this :  Does  a  structural  or 
functional  change  directly  induced  in  the  body  of  an 
individual  organism  as  the  result  of  some  peculiarity 

221 


222  SECRETS  OF  ANIMAL  LIFE 

in  function  (use  and  disuse),  or  in  environment  and 
nurture  generally,  ever  affect  the  germ-plasm  in  the 
reproductive  organs  in  such  a  specific  or  representa- 
tive way  that  the  offspring  will  thereby,  though  not 
subjected  to  the  nurtural  peculiarity  in  question, 
exhibit  the  same  modification  that  the  parent 
acquired,  or  even  an  approximation  towards  it? 
Modifications  are  dints  of  direct  extrinsic  origin,  in 
contrast  to  variations  or  mutations  which  are  ex- 
pressions of  germinal  change  fulness;  and  the  pre- 
cise point  is  whether  the  acquirer  of  the  modification 
can  entail  it  on  his  progeny  as  such  or  in  any  repre- 
sentative degree.  It  is  admitted  that  deep  dints 
may  have  secondary  effects  on  the  germ-cells  and 
on  the  unborn  offspring;  but  this  is  not  the  question 
at  issue.  It  is  also  probable  that  long-continued, 
deeply-saturating  peculiarities  of  nurture  may 
produce  substances  that  enter  into  the  germ-cell 
or  into  the  embryonic  body  (e.g.  the  mammal  in 
its  ante-natal  life  of  symbiosis  with  its  mother,  or 
the  unliberated  seed  of  the  flowering  plant),  but 
there  is  as  yet  no  convincing  evidence  that  the 
resulting  changes  grip  the  constitution  permanently. 
It  would  perhaps  facilitate  our  understanding  of 
organic  evolution  if  we  found  reason  to  believe  that 
at  least  some  advantageous  modifications,  hammered 
on  to  the  individual,  could  be  transmitted  ever  so 
little,  but  the  difficulty  is  to  find  convincing  evi- 
dence. So  it  has  come  about,  not  through  any 
preference  of  darkness  to  light,  but  by  pressure  of 
hard  facts,  that  the  majority  of  naturalists  now 


WITH  DARWIN  FORWARDS  223 

hold  a  position  of  skepticism  as  to  the  transmissi- 
bility  of  acquired  characters.  This  skepticism  was 
early  hinted  at  by  Kant,  His,  Pritchard,  and  others, 
and  afterwards  expressed  in  a  masterly  way  by 
Galton  and  by  Weismann.  For  many  years  there 
continued  a  searching  criticism  of  case  after  case 
of  alleged  transmission  of  acquired  characters,  and 
now  there  is  widespread  agreement  with  Sir  Ray 
Lankester's  pronouncement,  that  one  of  the  notable 
advances  of  post-Darwinian  aetiology  has  been 
getting  rid  of  all  trace  of  the  Lamarckian  theory 
of  the  transmission  of  individually  acquired  char- 
acters or  somatic  modifications.  Of  recent  years, 
however,  there  have  been  many,  and  of  course 
welcome,  signs  of  a  "  Back  to  Lamarck  "  reaction, 
originating  perhaps  in  Samuel  Butler,  and  diversely 
expressed  by  Semon,  Cunningham,  Hartog,  Francis 
Darwin,  Bergson,  Russell,  Darbishire,  and  others. 
We  may  be  permitted  to  refer  in  particular  to 
Rignano,  the  genial,  indefatigable,  and  disinterested 
editor  of  the  brilliant  journal  Scientia — a  sound 
organon  of  pacific  internationalism.  Now,  back  to 
Lamarck  let  us  certainly  go  to  try  to  understand 
his  position  more  thoroughly,  as  Russell  has  done  in 
his  Form  and  Function  (1916).  Back  to  Lamarck 
let  us  certainly  go  in  order  to  discover  whether  we 
cannot,  without  disloyalty  to  the  known  facts, 
re-utilize  the  Adriadne  thread  which  guided  the  early 
explorer  of  the  evolution-labyrinth.  But  do.  not 
let  us  return  to  Lamarck  by  brushing  aside  forty 
years'  skeptical  scrutiny  of  evidence,  or  under  a 


224  SECRETS  OF  ANIMAL  LIFE 

confused  impression  that  Darwinism  denies  "  the 
racial  value  of  good  nurture,"  or  under  the  influence 
of  the  cynical  suggestion  that  the  "  brutal  creed  " 
of  those  who  doubt  the  transmission  of  acquired 
characters  has  behind  it  the  motive  "  to  keep  its 
money  in  its  pocket  and  its  power  over  the  poor." 

There  are  probably  many  like  ourselves  who  have 
no  radical  unwillingness  to  return  as  penitents  to  the 
Lamarckian  faith,  if  that  does  not  mean,  as  it  need 
not,  any  recantation  of  Darwinism.  But  we  have 
to  be  converted  first,  and  the  often  cited  experi- 
ments made  by  Dr.  Kammerer  will  not  suffice.  It 
appears  to  us,  for  instance,  that  Dr.  Agar's  experi- 
ments, which  were  just  as  careful  as  Kammerer's, 
point  to  the  opposite  conclusion.  That  is,  at  any  rate, 
how  they  seem  to  Agar  to  point.  Kammerer's  work 
is  very  striking  and  very  carefully  conducted,  but 
to  execute  a  volte-face  with  decency  we  surely 
require  more  than  one  set  of  experiments  by  one 
investigator.  The  kind  of  result  that  Kammerer 
obtained  may  be  briefly  illustrated.  He  found  that 
a  yellow  background  and  a  damp  atmosphere  in- 
creased the  yellowness  of  the  common  spotted 
salamander,  and  that  the  change  was  to  a  consider- 
able degree  transmitted.  The  offspring,  which  are 
hatched  within  their  mother,  start  their  career 
nearly,  but  not  quite,  as  yellow  as  their  modified 
parent.  The  experiments  lasted  for  ten  years,  and 
it  would  be  preposterous  to  criticize  them  in  a  few 
lines.  Great  praise  is  due  to  Kammerer  for  the 
painstaking  care  with  which  he  met  the  objection 


WITH  DARWIN  FORWARDS  225 

that  the  light  saturating  through  the  semi-trans- 
parent tissues  of  the  parent  might  directly  affect  the 
germ-cells  within.  We  attach  importance  to  the  fact 
that  Professor  MacBride,  one  of  our  foremost 
zoologists,  has  been  definitely  convinced  that 
Kammerer  has  proved  that  acquired  qualities  are 
to  some  extent  transmitted;  but  in  view  of  what 
has  happened  before,  we  decline  to  hurry  back  to 
Lamarck. 

Failing,  then,  to  be  convinced  that  the  proposi- 
tion of  Lamarck  has  been  in  any  case  proved,  we 
return  in  the  meantime  to  the  Darwinian  theory 
that  the  natural  selection  of  variations  has  been  a 
vera  causa  in  evolution.  But  what  we  return  to  is 
not  the  theory  often  unjustly  treated  in  summary 
statement,  e.g. :  "  The  evidently-true  doctrine  of 
the  destruction  of  the  less  viable  was  held  to  explain 
the  origin  of  the  more  viable."  For  Darwin 
made  it  quite  clear  that  he  postulated  the  raw 
material  that  was  continually  supplied  to  the 
sifting  process,  and  it  is  only  a  little  farther  than 
postulating  that  we  can  go  to-day  when  we  inquire 
into  the  origin  of  intrinsic  variations  and  mutations. 
We  may  point  to  certain  variational  stimuli  which 
are  known  to  provoke  germinal  change,  and  to  the 
familiar  opportunities  which  the  ripening  and  the 
fertilization  of  the  germ-cells  offer  for  re-shufflings 
of  the  hereditary  cards;  but  when  we  probe  into 
the  origin  of  the  distinctively  new  it  is  difficult  at 
present  to  get  away  from  the  postulate  that  the 
implicit  organism  which  we  call  the  germ-cell  makes 


226  SECRETS  OF  ANIMAL  LIFE 

experiments  in  self-expression  just  as  the  explicit 
organism  is  ever  doing.  There  is  no  need  to  be 
frightened  by  the  word  fortuitous,  so  often  used  as 
a  reproach  to  Darwinism,  for  it  is  just  a  short  way 
of  saying,  as  Darwin  did,  that  "  our  ignorance  of 
the  laws  of  variation  is  profound."  Mr.  Hookham 
has  given  us  the  interesting  information  (New 
Statesman,  3rd  March  1917)  that  Darwin  approved 
of  his  vivid  illustration  of  Nature's  fortuitousness. 
"  Whereas  if  man  wanted  to  hit  a  mark,  he  aimed 
at  it;  and,  if  he  aimed  well  enough,  he  hit  it; 
Nature's  plan  was  to  throw  up  grains  of  sand  in  all 
the  winds  through  all  time,  and  eventually  she  hit 
it  too,  but  she  could  not  be  said  to  aim."  But  we 
do  not  think  that  we  can  infer  from  Darwin's  ap- 
probation of  Mr.  Hookham's  image  that  he  meant 
to  be  committed  to  pure  chance,  except  that,  as  he 
explains,  he  could  not  regard  the  outcrop  of  varia- 
tions as  due  to  design  or  purpose.  Taking  a  wider 
sweep,  he  wrote  to  another  correspondent:  "If  we 
consider  the  whole  universe,  the  mind  refuses  to 
look  at  it  as  the  outcome  of  chance."  His  emphasis 
on  "  the  principle  of  correlated  variability,  when 
one  part  varies  other  parts  vary,"  also  throws  light 
on  what  he  meant  by  "  chance."  But,  in  any  case, 
we  mean  by  Darwinism  not  the  ipsissinia  verb  a  of 
Charles  Darwin,  but  the  living  doctrine  that  has 
legitimately  developed  from  his  central  idea  of  the 
natural  selection  of  intrinsic  variations  or  mutations, 
— a  doctrine  which  is  in  process  of  assimilating  a 
multitude  of  new  facts  in  regard  to  the  defmiteness  of 


WITH  DARWIN  FORWARDS          227 

variation,  the  correlation  of  variations,  the  occur- 
rence of  unit  characters,  the  brusqueness  of  muta- 
tions, and  so  on.  There  is  a  growing  body  of 
evidence,  e.g.,  as  regards  chromosomes,  that  a 
variation  is  often  a  much  more  definite  change 
than  was  formerly  supposed,  and  the  element  of  the 
casual  or  fortuitous  seems  to  be  reduced  by  the 
limitation  that  the  new  departure  must  be  in  some 
measure  congruent  with  the  germinal  organization 
already  established.  It  is  not  a  "  guiding  principle  " 
we  assume,  but  simply  the  unity  or  individuality  of 
the  organism,  as  real  when  it  is  telescoped  down 
into  a  germ-cell  as  when  it  finds  epiphany  in  the 
full-grown  creature. 

Tending  also  to  a  shrinkage  of  the  apparently 
fortuitous  is  the  fact,  which  Darwin  clearly  realized, 
that  the  sifting  process  often  operates  in  reference 
to  an  intricate  web  of  life,  so  that  a  nuance — a 
shibboleth — may  have  survival  value;  that  natural 
selection  operates,  generally  speaking,  in  relation 
to  an  external  systema  Nature?  which  has  been  in- 
creasingly elaborated  through  the  ages,  which  is 
indeed  part  of  the  explanation  of  the  progressivcness 
of  evolution.  There  has  been  an  evolution  of  the 
sieves  as  well  as  of  the  sifted.  This  idea  is  of 
far-reaching  importance  in  relation  to  mankind, 
where  so  much  of  progress  is  registered  outside 
protoplasm  altogether  in  organizations  and  institu- 
tions, permanent  products  and  cities,  literature  and 
art,  the  whole  forming  a  vast  sifting  apparatus 
which  is  itself  subject  in  detail  to  critical  selection 


228  SECRETS  OF  ANIMAL  LIFE 

in  terms  of  the  highest  values.  As  to  the  question 
whether  the  factors  operative  in  ordinary  organic 
evolution  are  more  than  complications  or  com- 
positions of  factors  which  operate  in  inorganic 
genesis,  we  would  answer,  Much  more.  For  Natural 
Selection  operates  on  what  is  not  accounted  for 
mechanically,  and  the  sifting  process  itself  is  more 
than  mechanical.  For  the  explicit  organism  can 
often  be  seen  to  play  the  new  cards  which  the 
implicit  organism  has  put  into  its  hands.  Organ- 
isms are  at  times  selected  by  their  environment; 
at  other  times  they  select  it.  They  often  help 
to  make  their  own  sieves.  All  our  formal  state- 
ments of  the  tactics  of  organic  evolution  are  too 
stiff.  They  tend  to  conceal  the  heart  of  the  matter, 
of  which,  in  Darwin's  footsteps,  we  are  ever  getting 
new  glimpses,  that  living  creatures  with  a  will  to 
live,  with  an  insurgent  self-assertiveness,  with  a 
spirit  of  adventure,  with  an  endeavor  after  well- 
being,  do  trade  with  time  and  have  commerce 
with  circumstance,  as  genuine  agents,  sharing  in 
their  own  evolution. 


XXX 

THE  MENDELIAN  CLUE 

IN  pre-Darwinian  days  people  spoke  of  Heredity 
with  a  capital  letter  as  if  it  were  a  power  or 
principle  that  did  things — just  as  many  still 
speak  of  Evolution.  It  was  one  of  Darwin's 
many  services  that  he  showed  the  organic  linkage 
between  one  generation  and  another  to  be  amenable 
to  scientific  inquiry  and  statement.  To  him  heredity 
was  the  genetic  relation  between  successive  genera- 
tions— a  relation  that  secures,  through  the  vehicle 
of  the  germ-cells,  a  persistence  of  a  large  measure 
of  specificity  both  in  form  and  habit,  both  of  micro- 
scopic architecture  and  chemical  metabolism.  His 
particular  theory  (pangenesis)  of  what  distinguished 
the  germ-cells  from  the  specialized  body-cells  \vas 
not,  indeed,  acceptable,  but  it  was  with  Darwin 
that  the  scientific  study  of  heredity  practically 
began.  To  his  cousin,  Francis  Galton,  and  to 
Professor  Weismann  we  owe  the  elucidation  of  an 
idea  which  seems  to  have  occurred  to  several  others 
— the  idea  of  germinal  continuity — that  the  reason 
for  like  begetting  like  is  the  persistence  of  a  specific 
organization  through  a  lineage  of  unspecialized 
germ-cells.  While  most  of  the  germinal  material  of 
the  fertilized  ovum  is  used  to  build  up  the  body  of 

230 


230          SECRETS  OF  ANIMAL  LIFE 

the  offspring,  undergoing  in  a  most  puzzling  way 
differentiation  into  nerve  and  muscle,  blood  and 
bone,  a  residue  is  kept  intact  and  unspecialized  to 
form  the  primordium  of  the  reproductive  organs  of 
the  offspring,  whence  will  be  launched  in  due  time 
another  similar  vessel  on  the  adventurous  voyage 
of  life.  So  it  comes  to  be  that  the  parent  is  rather 
the  trustee  of  the  germ-plasm  than  the  producer 
of  the  child.  In  a  new  sense  the  child  is  a  chip 
of  the  old  block.  Or,  as  Bergson  puts  it  in  less 
static  metaphor,  "  life  is  like  a  current  passing 
from  germ  to  germ  through  the  medium  of  a 
developed  organism."  Though  it  is  now  clear 
that  Weismann  exaggerated  the  contrast  and 
apartness  of  body-cells  and  germ-cells,  the  general 
idea  of  the  continuity  of  the  germ-plasm  remains 
as  one  of  the  most  important  contributions  to  post- 
Darwinian  biology.  It  is  the  explanation  of  the 
inertia  of  the  main  mass  of  the  inheritance,  which 
is  carried  on  with  little  change  from  generation  to 
generation.  For  men  do  not  gather  grapes  off 
thorns  or  figs  off  thistles.  Similar  material  to 
start  with;  similar  conditions  in  which  to  develop; 
therefore  like  begets  like. 

While  the  epoch-making  experimental  work  of 
Mendel,  which  would  have  so  much  delighted 
Darwin's  heart,  lay  buried  in  the  records  of  the 
naturalists'  society  at  Briinn,  there  was  developed 
in  Britain  a  statistical  study  of  inheritance,  especi- 
ally associated  with  Sir  Francis  Galton  and  Profes- 
sor Karl  Pearson.  It  was  Galton  who  began  to  study 


THE  MENDELIAN  CLUE  231 

the  inheritance  of  particular  characters  through 
successive  generations  and  to  measure  quantitatively 
the  degrees  of  hereditary  resemblance.  He  was 
led  to  the  law  of  ancestral  inheritance,  according 
to  which  the  average  contributions  to  each  inherited 
faculty  are  a  half  from  the  parents,  a  quarter  from 
the  grandparents,  an  eighth  from  the  great-grand- 
parents, and  so  on  backwards  in  the  same  diminish- 
ing ratio  (afterwards  somewhat  modified  by  Pear- 
son) ;  and  another  deduction  was  the  law  of  filial 
regression  or  the  tendency  to  approximate  to  the 
mean  of  the  stock.  It  is  necessary,  however,  to  bear 
in  mind  that  these  average  statistical  deductions  do 
not  hold  in  regard  to  non-blending  hereditary 
characters,  and  that  they  do  not  seem  to  take 
sufficient  account  of  the  fundamental  distinction 
between  inborn  variations  and  individually  acquired 
modifications.  The  latter  are  somatic  dints  due  to 
peculiarities  of  nurture,  and  have  not  been  proved 
to  be  transmissible;  the  former  are  expressions  of 
germinal  change  fulness,  and  are  in  some  cases 
demonstrably  transmissible.  Of  great  value,  how- 
ever, has  been  the  statistical  demonstration  of  the 
heritability  of  subtle  constitutional  qualities — such 
as  fecundity  and  longevity — and  the  proof  that 
clearly-defined  mental  qualities  may  be  handed  on 
to,  and  distributed  among,  the  offspring  just  in 
the  same  way  as  bodily  characters. 

The  first  year  of  this  century  will  be  memorable 
in  the  annals  of  biology  for  the  rediscovery  of  the 
Mendelian  clue  by  Correns,  De  Vries,  and  Tscher- 


232          SECRETS  OF  ANIMAL  LIFE 

mak;  and  more  progress  has  been  made  with  the 
science  of  heredity  since  the  century  began  than  in 
all  previous  years.  For  this  we  have  to  thank  numer- 
ous investigators — among  whom  Bateson  stands  pre- 
eminent. What  are  the  central  ideals  of  Mendel- 
ism?  How  far  does  it  apply?  What  practical 
promise  does  it  offer? 

There  are  three  fundamental  ideas  in  the  Men- 
delian  conception  of  inheritance  :  i.  The  first  is  the 
idea  of  "  unit  characters."  An  inheritance  is,  in  part 
at  least,  built  up  of  numerous  more  or  less  clear-cut, 
crisply  defined,  non-blending  characters,  which  are 
continued  in  some  of  the  descendants  as  discrete 
wholes,  neither  merging  nor  dividing.  If  a  man 
has  his  fingers  all  thumbs,  i.e.,,  with  two  joints 
instead  of  three,  this  unit  character  of  "  brachy- 
dactylism "  is  sure  to  be  continued  in  a  certain 
proportion  of  his  descendants.  Night-blindness,  or 
the  inability  to  see  in  faint  light,  has  been  traced 
through  a  lineage  since  near  the  beginning  of  the 
seventeenth  century.  A  definite  type  of  very 
intelligent  dwarf  has  been  known  to  reappear  for 
four  or  five  generations.  The  persistence  of  the 
Hapsburg  lip  is  a  familiar  instance  of  the  way  in 
which  a  unit  character  comes  to  stay.  These  unit 
characters  behave  as  if  they  were  discrete  entities 
which  can  be  shuffled  about  and  distributed  to  the 
offspring  to  some  degree  independently  of  one  an- 
other. Some  suppose  that  they  are  represented  by 
specific  particles  in  the  germinal  material;  others 
would  not  go  further  than  saying  that  they  are 


THE  MENDELIAN  CLUE  233 

represented  by  differences  in  the  ultra -microscopic 
architecture.  It  is  quite  likely  that  several  factors 
may  be  concerned  in  one  character,  or  that  one  factor 
may  influence  more  than  one  character.  2.  The 
second  idea  in  Mendelism  is  that  of  dominance. 
When  Mendel  crossed  a  pure-bred  tall  pea  with  a 
pure-bred  dwarf  pea,  the  offspring  were  all  tall ;  and 
he  called  the  quality  of  tallness  dominant  to  the 
recessive  quality  of  dwarfness,  which  the  hybrid 
offspring  keep,  as  it  were,  up  their  sleeve.  The 
dwarfness  is  not  expressed,  but  it  is  certainly  in  the 
inheritance,  for  it  reappears  in  a  quarter  of  the 
progeny  of  the  hybrid  generation,  if  these  are  inbred 
or  allowed  to  self-fertilize.  If  a  Japanese  waltzing 
mouse  is  crossed  with  a  normal  mouse,  all  the  hybrid 
progeny  are  normal,  the  waltzing  peculiarity  being 
recessive  to  normality.  If  the  hybrids  be  inbred, 
some  of  their  progeny  are  waltzers  in  the  average 
proportion  of  a  quarter — and  these  waltzers  might 
be  sold  as  pure  waltzers — although  both  their  parents 
and  one  of  their  grandparents  were  normal.  Simi- 
larly, about  a  third  of  the  rest  of  the  progeny  are 
purely  normal,  while  two-thirds  are  like  the  first 
generation  of  hybrids — to  all  appearance  normal,  but 
with  the  waltzing  character  up  their  sleeve.  It  often 
happens  that  the  two  parents  differ,  not  in  presenting 
a  pair  (or  more)  of  contrasted  or  alternative  char- 
acters, but  in  the  one  having  certain  unit  characters 
which  the  other  has  not.  This  works  out  in  the 
same  way — the  unit  character  that  is  present  being, 
as  it  were,  dominant  to  its  own  absence.  In 


234  SECRETS  OF  ANIMAL  LIFE 

illustration  of  characters  that  exhibit  Mendelian 
inheritance,  the  following  may  be  cited,  the  domi- 
nant condition  being  named  first  in  each  case :  Horn- 
lessness  and  the  presence  of  horns  in  cattle,  normal 
hair  and  long  "  Angora  "  hair  in  rabbits  and  guinea- 
pigs,  kinky  hair  and  straight  hair  in  man,  crest  and 
no  crest  in  poultry,  extra  toes  in  poultry  and  the 
normal  number  four,  bandless  shell  in  wood-snail 
and  banded  shell;  yellow  cotyledons  in  peas  and 
green  ones,  round  seeds  in  peas  and  the  wrinkled 
form,  absence  of  awn  in  wheat  and  its  presence, 
susceptibility  to  rust  in  wheat  and  immunity  to 
this  disease,  two-rowed  ears  of  barley  and  six-rowed 
ears,  markedly  dentate  margin  in  nettle  leaves 
and  slightly  toothed  margin.  Why  one  character 
should  be  dominant  and  another  recessive  is  not 
known;  a  positive  feature  may  be  recessive,  and 
a  negative  feature  may  be  dominant.  It  should  be 
noted  that  in  a  large  number  of  cases  of  alternative 
or  Mendelian  inheritance  the  dominance  in  the 
offspring  is  not  complete;  thus,  if  black  Andalusian 
fowls  be  crossed  with  white  ones  the  progeny  are 
"  blue  "  Andalusians.  3.  The  third  idea  in  Mendel- 
ism  is  the  theory  of  segregation.  Mendel  supposed 
that  the  hybrid  or  cross-bred  offspring  produced  two 
kinds  of  germ-cells  in  approximately  equal  numbers 
—one-half  with  the  determiner  or  factor  corre- 
sponding to  the  dominant  character,  and  the  other 
half  without  it,  or  with  the  factor  corresponding  to 
the  recessive  character.  In  other  words,  each  germ- 
cell  is  "  pure "  with  respect  to  any  given  unit 


THE  MENDELIAN  CLUE  235 

character.  If  this  be  so,  and  if  fertilization  be 
fortuitous,  then  the  Mendelian  proportions  must  be 
exhibited  by  the  offspring  of  the  hybrid  generation, 
namely,  25  per  cent,,  pure  recessives,  25  per  cent, 
pure  dominants,  and  50  per  cent,  impure  dominants 
(like  the  original  hybrids),  which,  if  inbred,  will 
have  offspring  in  the  same  1:2:1  proportion  as 
regards  the  particular  unit  character  observed. 

It  is  often  asked  whether  there  are  not,  as  used 
to  be  believed  without  question,  other  modes  of 
inheritance  besides  this  Mendelian  mode,  and  this 
continues  to  be  the  subject  of  investigation.  Does 
the  mulatto  exhibit — as  regards  skin-color — a 
blend  of  the  characters  of  his  parents,  or  is  the 
matter  less  simple  than  it  seems?  Are  not  the 
hybrids  between  long-eared  and  short-eared  rabbits 
very  exact  intermediates  between  their  parents,  and 
do  not  hybrid  cockatoos  show  diagrammatic  blend- 
ing? Or  are  such  cases  sufficiently  interpreted  on 
Mendelian  lines  as  due  to  incomplete  dominance,  or 
to  the  fact  that  one  character  may  have  multiple 
factors  which  do  not  get  cleanly  segregated  in  the 
history  of  the  germ-cells.  It  is  one  of  the  merits  of 
Professor  James  Wilson's  recent  introduction  to 
Mendelism  x  in  its  practical  aspects  that  it  shows  how 
results  which  do  not  seem  consistent  with  Mendelian 
theory  may  nevertheless  be  brought  into  conformity 
with  it.  Disturbances  in  the  Mendelian  distribu- 
tion may  be  due  to  factors  cancelling  one  another, 
jostling  one  another,  coupling  with  one  another, 
1 A  Manual  of  Mendelism,  1916.  A.  &  C.  Black. 


236  SECRETS  OF  ANIMAL  LIFE 

and  so  on.  The  doubt  left  in  one's  mind  is  whether 
the  auxiliary  hypotheses  which  make  difficult  cases 
conformable  are  triumphs  of  human  ingenuity  or 
indices  of  the  subtlety  of  life.  When  we  are  led 
by  other  authorities  to  contemplate  the  disintegra- 
tion or  fractionization  of  the  factors  of  certain  unit 
characters,  our  faith  is  strained  by  what  seems  so 
like  a  contradiction  in  terms.  But  the  scientific 
position  is  to  experiment  and  see.  Very  interesting 
on  another  line  are  the  experiments  of  T.  H.  Mor- 
gan l  and  his  collaborators  on  the  fruit-fly  Droso- 
phila,  showing  that  "  every  character  is  the  realized 
result  of  the  reaction  of  hereditary  factors  with  each 
other  and  with  their  environment."  Flies  of  a 
race  with  a  peculiar  hereditary  abnormality  will 
develop  normally  if  raised  in  a  dry  environment, 
but  the  presence  within  them  of  the  factor  for 
abnormality  may  be  demonstrated  by  rearing  their 
offspring  in  moisture.  In  other  words,  the  ex- 
pression of  even  Mendelian  characters  requires  an 
appropriate  nurture. 

Professor  Wilson  lays  stress  on  the  fact  that 
theoretical  difficulties  need  not  hinder  the  breeder 
from  utilizing  the  Ariadne  thread  which  Mendel  has 
put  into  his  hand.  For  it  is  becoming  increasingly 
clear  that  Mendelism  can  enable  a  breeder  or 
cultivator  to  reach  his  desired  result  more  surely, 
more  rapidly,  and  more  economically.  His  new 
knowledge  shows  him  how  desirable  qualities  of  the 
unit  character  type  can  be  grafted  on  to  a  stock, 
1  The  Mechanism  of  Mendelian  Heredity.  Constable,  1915. 


THE  MENDELIAN  CLUE  237 

and  how  undesirable  qualities  may  be  slipped  off, 
and  never  was  it  more  necessary  than  now  to  put 
all  our  available  science  into  the  art  of  cultivation 
and  breeding.  The  average  yield  of  wheat  in 
Britain  is  about  thirty-two  bushels  to  the  acre. 
Professor  Wilson  tells  us  that  it  might  be  raised  to 
forty  or  even  fifty.  "  For  every  day  by  which  the 
life  of  a  variety  of  wheat  is  shortened  between  seed- 
time and  harvest,  the  wheat-growing  area  in  Canada 
reaches  fifty  or  sixty  miles  farther  northwards/' 
The  work  done  in  Denmark  shows  how  the  wealth 
of  our  country,  so  far  as  it  proceeds  from  dairy 
cattle,  might  be  very  nearly  doubled.  These  are 
two  instances  out  of  many  which  might  be  cited  to 
illustrate  the  practical  value  of  Mendelism — and  it 
is  only  beginning. 


XXXI 
THE  FOUNTAIN  OF  CHANGE 

ONE  of  the  fundamental  problems  of  Biology 
is  the  origin  of  the  distinctively  new.  A 
clever  and  well-proportioned  dwarf  is  born  in  a 
family,  and  the  interesting  type  may  reappear  in 
a  certain  proportion  of  his  descendants  for  at  least 
four  generations.  The  unsolved  problem  is  :  What 
conditioned  the  dwarf?  It  is  the  same  problem 
as  the  origin  of  the  mathematical  or  the  musical 
genius,  the  old  problem  of  new  departures.  It  is 
difficult  to  draw  the  line,  but  it  seems  possible  to 
discriminate  between  minor  novelties  or  "  fluctua- 
tions/' which  differ  but  slightly  from  the  parent 
type  or  may  be  connected  with  it  by  intermediate 
gradations,  and  the  major  novelties  or  "  mutations  " 
which  represent  more  or  less  of  a  new  pattern  and 
are  discontinuous.  The  contrast  is  not  so  much 
in  the  amount  as  in  the  kind  of  change.  The 
copper  beech,  which  made  its  appearance  in  the 
seventeenth  century,  may  not  differ  very  materially 
from  an  ordinary  beech,  but  it  was  a  discontinuous 
variant  which  arose  abruptly  and  came  to  stay. 
Similarly,  the  white  rat  does  not  seem  to  want  very 
much  to  make  it  a  brown  rat — the  species  whence  it 
sprang — but  it  was  in  its  day  a  new  departure,  and 

238 


THE  FOUNTAIN  OF  CHANGE         239 

it  has  bred  true.  Our  knowledge  of  the  origin  of 
cultivated  plants  is  meager,  but  there  is  considerable 
reason  to  believe  that  they  began  in  mutations. 
We  know  that  this  was  the  origin  of  the  Laciniate 
Greater  Celandine,  which  appeared  without  warning 
in  1590  and  has  been  breeding  true  ever  since. 
Some  fluctuations  seem  to  be  transmissible,  and  to 
reappear  in  varying  degrees  in  the  offspring,  so  that 
the  possibility  of  man's  reaching  a  desired  end  by 
persistent  selection  remains;  but  the  balance  of 
present-day  evidence  inclines  to  the  view  that  the 
essential  step  may  be  taken  brusquely.  The 
momentous  prehistoric  origin  of  "  thrashable " 
wheat,  for  instance,  may  have  come  about  abruptly 
and  in  one  plant.  Similarly,  in  regard  to  the  origin 
of  domesticated  races  of  animals  our  knowledge  is 
very  unsatisfactory,  but  there  are  strong  reasons  for 
believing  that  the  essential  steps  were  due  not  to 
sifting  fluctuations,  but  to  breeding  from  transilient 
mutations.  In  recent  years  we  have  come  to  know 
of  mutants  arising  in  wild  species  and  persisting. 
Thus  the  black  mutant  of  the  Peppered  Moth 
has  been  very  successful,  and  a  similar  variety  of 
a  certain  West  Indian  Sugar-bird  has  practically 
supplanted  the  parent  species.  Now,  whatever  we 
may  conclude  as  to  the  cause  of  these  two  novelties, 
we  cannot  at  all  events  say  that  they  were  the 
results  of  a  slow  selection  of  individuals  fluctuating 
in  the  direction  of  blackness.  It  is  one  of  the 
marked  changes  in  modern  evolution-lore  that 
increasing  importance  is  being  attached  to  mutations 


240  SECRETS  OF  ANIMAL  LIFE 

and  less  to  fluctuations.  (As  for  individually 
acquired  modifications,  imposed  on  the  body  from 
without,  instead  of  emerging  from  the  changeful 
germ-plasm  within,  they  do  not  seem  to  be  in 
themselves  of  much  direct  racial  importance,  for 
there  is  no  cogent  evidence  of  their  transmissibility.) 
Darwin  knew,  of  course,  of  some  of  the  transilient 
or  saltatory  variations,  which  are  now  called  muta- 
tions, but  he  deliberately  passed  them  by  and  laid 
emphasis  on  the  selection  of  fluctuations.  His 
strongest  reason  for  so  doing  was  his  conviction 
that  the  sudden  "single  variations"  or  sports 
would  be  readily  swamped  or  leveled  down  by 
inter-crossing.  It  is  now  known,  however,  that  one 
of  the  characteristics  of  mutations  is  their  capa- 
bility of  complete  inheritance  in  a  varying  percent- 
age of  the  progeny. 

To  the  Dutch  botanist  De  Vries  especial  credit  is 
due  for  his  recognition  of  the  evolutionary  im- 
portance of  mutations  and  for  his  study  of  their 
behavior  in  inheritance.  It  is  an  often-told  story 
how  he  found,  in  1886,  in  a  potato-garden  near 
Hilversum,  in  Holland,  a  race  of  the  Evening  Prim- 
rose, (Enothera  lamarckiana,  in  which  the  mood  was 
all  mutation.  In  spite  of  Galton's  insistence  on  the 
reality  of  transilient  variations  and  Bateson's  mar- 
shaling of  instances  of  discontinuity,  the  tendency 
had  grown  strong  to  dogmatize  about  the  con- 
tinuity of  organic  change,  just  as  previously  about 
the  fixity  of  species.  "  Natura  non  facit  saltus," 
they  said;  but  De  Vries  discerned  Natura  saltatrix 


THE  FOUNTAIN  OF  CHANGE         241 

in  the  Evening  Primrose  of  Hilversum,  which,  by 
the  way,  turns  out  to  have  been  in  the  eighteenth 
century  a  wild  species  in  North  America.  Three 
points  may  be  emphasized.  First,  that  some  of  the 
mutants  which  De  Vries's  sportive  (Enotheras  threw 
off,  as  an  artist  might  tear  sketches  from  his  note- 
book, were  ephemeral  failures,  while  others  were 
viable  and  bred  true,  and  could  not  be  otherwise 
described  than  as  species  in  the  making,  fingers 
searching,  as  it  were,  for  their  appropriate  environ- 
mental glove.  Second,  in  many  cases  the  mutants 
were  of  particular  interest  because  they  showed 
through  and  through  divergences — in  leaf  and 
stem  and  flower — certainly  suggestive  of  some 
general  disturbance  of  germinal  organization.  Just 
as  if  the  (Enothera  was  born  again !  Third,  that  the 
creativeness  or  sportiveness  of  the  Evening  Prim- 
rose is  not  restricted  to  De  Vries's  particular  race  of 
(Enothera  lamarckiana.  It  occurs  in  other  species 
of  Evening  Primrose,  and  also  in  snapdragon  and 
barley,  in  strawberry  and  maize,  in  pomace-fly  and 
potato-beetle,  in  rat  and  man  himself,  and  so  forth. 
Mutations  may  be  induced  experimentally,  as 
Professor  Tower  did  with  his  potato-beetles  and 
as  Mme.  Henri  recently  did  with  the  bacillus  of 
anthrax,  or  they  may  manifest  themselves  in  wild 
nature,  as  in  the  already  mentioned  Peppered  Moth 
and  Sugar-bird.  The  result  may  be  a  plus  or  a 
minus,  a  dominant  or  a  recessive  or  neither,  patho- 
logical or  normal.  The  mutation  may  occur  after 
crossing  or  in  a  pure  race;  it  may  show  itself 


242  SECRETS  OF  ANIMAL  LIFE 

potentially  before,  during,  or  after  fertilization. 
In  short,  there  is  nothing  hard  and  fast  about 
the  origin  or  nature  of  mutations:  their  common 
features  are  their  brusque  appearance,  their  dis- 
continuity with  the  parent  stock,  and  their  capa- 
bility of  being  transmitted  intact  to  a  certain 
proportion  of  the  offspring.  This  brings  us  to  notice 
the  recent  masterly  work  of  Dr.  Ruggles  Gates,  who 
has  been  for  many  years  a  persistent  investigator 
of  the  mutations  of  GEnothera.  In  his  Mutation 
Factor  in  Evolution  (Macmillan,  1915)  he  expounds 
the  notable  advance  which  his  researches  have 
secured.  He  has  been  able  to  show  in  circumstan- 
tial detail  that  the  peculiarities  marking  the  various 
mutants  are  correlated  with  observable  alterations 
in  the  organization  of  the  fertilized  egg-cell,  especi- 
ally as  regards  the  nuclear  rodlets  or  chromosomes 
of  which  each  kind  of  organism  has  a  definite  num- 
ber. The  fundamental  number  of  chromosomes  for 
the  genus  (Enothera  is  14;  this  has  become  15  in  lata 
and  semilata,  21  in  semigigas,  28  in  gigas,  and  so  on. 
This  change  is  observable  in  the  fertilized  egg-cell 
and  is  echoed  throughout  the  whole  plant.  In  this 
connection  a  reference  may  be  permitted  to  what 
obtains  in  man.  Competent  observers  have  stated 
that  the  cells  of  the  male  negro  have  22  chromo- 
somes, and  it  is  probable  that  the  negress  has,  at 
least  in  some  cases,  24.  Now  in  the  case  of  the  white 
man  and  woman  the  enumerations  of  chromosomes 
by  very  careful  observers  point  to  the  numbers 
47  and  48  respectively.  It  seems  to  be  very  difficult 


THE  FOUNTAIN  OF  CHANGE         243 

to  reach  certainty  in  regard  to  this  simple  point, 
but  there  is  no  harm  in  asking,  as  Dr.  Gates  does, 
whether  the  white  man  may  have  originated  from  a 
black  race  by  a  "  tetraploid  mutation  and  its  conse- 
quences." The  nuclear  change  need  not,  of  course, 
affect  the  number  of  the  chromosomes;  it  may 
affect  shape  and  size  and  structure.  More  funda- 
mentally— but  no  longer  visibly — a  chromosome 
may  undergo  a  change  in  its  stereochemic  archi- 
tecture or  in  its  functional  powers.  We  know  of 
remarkable  mutations  in  bacteria,  which  some- 
times change  suddenly  in  their  physiological  prop- 
erties. 

The  mutation  theory  is  concerned  with  the  origin 
of  new  characters,  and  Mendelism  is  concerned  with 
their  behavior  in  inheritance;  so  the  two  theories 
touch,  and  it  is  interesting  to  notice  Dr.  Gates' 
position.  In  the  first  place,  it  seems  clear  that  there 
is  no  warrant  for  supposing  that  Qtnothera  lamarcki- 
ana  has  had  a  mixed  ancestry  and  that  its  mutabil- 
ity (still  unexhausted)  is  a  result  of  this.  Mutations 
may  occur  apart  altogether  from  crossing,  though 
crossing  may  increase  their  frequency  or  even 
initiate  a  condition  of  germinal  instability.  In  the 
second  place,  the  Mendelian  classification  of  all  new 
characters  into  dominants  (due  to  the  addition  of  a 
factor)  and  recessive s  (due  to  the  loss  of  a  factor) 
is  much  too  hard  and  fast  to  cover  all  the  facts. 
Germinal  changes  are  of  many  and  diverse  kinds, 
and  are  not  exhausted  by  addition  or  loss  of  unit 
factors.  Some  mutations  illustrate  Mendelian 


244  SECRETS  OF  ANIMAL  LIFE 

inheritance  and  some  do  not.  Moreover,  the 
Mendelian  doctrine  that  all  characters  segregate  in 
inheritance  and  are  uninfluenced  by  crossing  is  far 
from  being  substantiated  by  Gates'  results.  He 
finds  Mendelian  splitting,  it  is  true,  but  much  more 
besides.  He  finds  illustrations  of  blending  and 
hints  of  the  mutual  influence  of  hereditary  char- 
acters ;  he  finds  curious  results  called  "  mutation 
crosses  "  and  "  twin  hybrids,"  which  are  anything 
but  Mendelian.  In  short,  the  Mendelian  categories 
are  far  too  rigid,  savoring  too  much  of  the  in- 
animate domain. 

The  step  gained  is  the  demonstration  that  the 
bodily  peculiarities  of  mutants  are  correlated 
with  visible  disturbances  in  the  germinal  organiza- 
tion. The  next  step  is  to  discover  all  we  can  in 
regard  to  these  germinal  disturbances.  Dr.  Gates 
has  described  changes  in  the  number,  shape,  size, 
arrangement,  and  structure  of  the  chromosomes; 
but  he  is  careful  to  point  out  that  we  must  push 
beyond  these  to  chemical  or  functional  changes 
in  particular  chromosomes  or  parts  of  chromosomes. 
Furthermore,  changes  may  perhaps  occur  in  the 
mysterious  karyolymph  or  gel  which  forms  the 
ground-work  of  the  nucleus.  But  behind  the 
question  of  the  nature  of  the  germinal  changes 
looms  the  problem  of  their  origin.  The  Proteus 
of  the  organism  has  changed  into  the  Proteus  of 
the  chromosomes.  Do  these  germinal  disturbances 
come  about  in  response  to  subtle  environmental 
stimuli  penetrating  in  from  without,  or  does  the 


.THE  FOUNTAIN  OF  CHANGE         245 

germ-cell — the  creature,  we  maintain,  in  its  one- 
cell  phase  of  being — play  a  more  active  part  (like 
a  Foraminifer  artist  building  a  shell  of  Synaptid 
anchors)  and  experiment  in  self-differentiation? 
Dr.  Gates  has  a  stern  scientific  mood  and  does 
not  often  let  himself  go  in  the  region  of  speculation, 
but  he  does  not  forget  that  the  organism  is  alive! 
"Just  as  an  alpine  climber  dangling  over  a  chasm 
may,  by  changing  his  hold,  swing  himself  on  to  a 
shelf  from  which  he  can  make  a  fresh  start  in  some 
other  direction,  so  we  may  think  of  the  organism 
trying  many  unconscious  experiments  in  its  off- 
spring, some  of  which  are  hurled  by  the  gravita- 
tional effect  of  natural  selection  into  the  abyss  of 
extinction,  while  others  with  a  more  fortunate 
turn  rest  on  a  ledge  of  safety  whence  new  essays 
of  variability  begin."  It  is  true  that  the  author 
comes  back  to  the  chemical  and  structural  com- 
plexity of  the  protoplasm  and  its  unique  irrita- 
bility, but  we  wish  that  he  had  dwelt  longer  on  his 
picture  of  the  organism  as  a  climber.  It  may  have 
no  fixed  purpose  of  getting  to  the  top,  yet  there  may 
be  inseparable  from  it  a  restless  experimenting  in 
self-expression,  bearing  in  the  germ-cell  the  same 
relation  to  the  insurgent  efforts  of  the  full-grown 
creature  that  the  tentatives  of  dreamland  bear  to  the 
achievements  of  open-eyed  endeavor. 


XXXII 
PROBLEM  OF  CAVE  BLINDNESS 

PRE-EMINENT  as  man  is,  compared  with 
other  creatures,  there  are  few  of  the  deeper 
problems  of  Natural  History  which  have  not  a 
practical  bearing  on  human  affairs.  The  touch  of 
animate  protoplasm  makes  the  whole  living  world 
kin;  and  if  we  knew  with  certainty  how  it  has  come 
about  that  many  cave-animals  are  blind  or  have  ill- 
developed  eyes,  we  should  be  able  to  think  more 
clearly  in  regard  to  some  dwellers  in  darkness 
nearer  home.  Let  us  turn,  then,  sympathetically 
to  the  fact  of  cave  blindness,  and  to  some  notable 
recent  contributions  to  the  evolutionary  problem 
which  it  raises.  Dry  caves  have  never  more  than 
casual  tenants,  but  damp  caves  harbor  many 
creatures — from  salamanders  to  wood-lice — which 
are  in  the  strict  sense  at  home  there.  The  list  of 
Troglodytes  is  more  extensive  than  honorable,  for 
leaving  out  of  account  the  numerous  bats  and  a  few 
peculiar  mice,  which  rest  in  the  cave  but  feed  by 
night  outside  of  it,  thus  making  the  best  of  two  dark 
worlds,  we  find  that  the  bulk  of  the  cavernicolous 
fauna  is  rather  weedy.  There  are  few  cave-dwelling 
animals  of  the  desperado  type  that  we  associate 
;with  Adullam;  most  of  them  are  handicapped  by 


PROBLEM  OF  CAVE  BLINDNESS      247 

some  frailty  of  constitution  or  by  having  fallen 
behind  the  times.  Some  are  relices  of  a  Glacial 
fauna.  Their  closest  analogues  are  to  be  found 
among  the  shy  "  cryptozoic  "  creatures  who  hide 
under  stones  and  bark  and  seldom  venture  forth. 
The  true  cave-dwellers  are  more  or  less  adapted  to 
the  permanent  conditions — darkness,  constant  tem- 
perature, humid  atmosphere,  and  absence  of  green 
plants.  They  include  (apart  from  bats  and  mice) 
the  weird  Amphibian  Proteus  of  the  great  caves  of 
Carniola  and  Dalmatia,  three  or  four  North  Amer- 
ican salamanders,  quite  a  lot  of  small  fishes,  a  few 
snails,  numerous  beetles  and  a  sprinkling  of  other 
kinds  of  insects,  many  spiders  (who  insinuate  them- 
selves everywhere),  and  a  few  Crustaceans,  besides 
some  still  smaller  deer.  After  making  sundry  reser- 
vations, we  recognize  that  those  cavernicolous  ani- 
mals that  have  open-air  relatives  with  which  they 
may  be  compared  tend  to  be  dwarfish,  to  be  mo- 
notonous or  deficient  in  coloration,  to  have  ex- 
quisitely developed  tactility,  and  to  have  more  or 
less  rudimentary  eyes.  It  is  on  this  tendency  to- 
wards blindness  that  we  wish  to  focus  attention. 

There  are  considerable  differences  in  the  degree  of 
degeneration  which  the  eyes  of  cave  animals  exhibit, 
but  there  are  few  that  have  remained  unaffected.  In 
the  pale  Proteus,  which  has  no  pigment  in  its  skin, 
the  eye  is  without  a  lens  and  does  not  reach  the 
surface  of  the  head.  This  reminds  us  of  the  buried 
eye  of  the  deep-water  hagfish  and  of  the  way  in 
which  the  very  lids  of  the  eyes  of  the  Cape  Golden 


248  SECRETS  OF  ANIMAL  LIFE 

Mole  are  closed.  Practically  complete  blindness  is 
illustrated  by  a  North  American  cave-crayfish,  a 
cave-prawn  from  Carniola,  and  some  other  Crusta- 
ceans. In  some  of  the  cave-beetles  the  degeneration 
has  affected  not  only  the  eye  but  the  optic  ganglion 
as  well.  The  cave-fishes  are  of  special  interest,  for 
they  show  all  grades  of  optic  degeneration  down  to 
complete  blindness.  In  some  of  them,  moreover, 
the  eyes  of  the  young  forms  are  less  degenerate 
than  those  of  the  adults — a  state  of  affairs  which  has 
been  observed  in  some  other  types  besides  fishes. 
It  suggests  that  there  may  be  a  process  of  individual, 
as  distinguished  from  racial,  degeneration, 
i  There  is  no  doubt  as  to  the  "  naturalness  "  of  the 
old  theory  that  the  "  blindness  "  of  cave-animals  is 
the  cumulative  hereditary  result  of  the  disuse  which 
living  in  darkness  involves.  Thus  we  cannot  over- 
look the  fact  that  some  of  the  blind  forms  have  very 
near  relatives  which  live  in  the  light  of  day  and  have 
well-developed  eyes.  To  take  an  analogous  case, 
that  of  deep  and  shallow  water :  Doflein  found  in 
Sagami  Bay  two  varieties  of  a  small  crab,  one  living 
in  the  darkness  of  deep  water  and  with  very  rudi- 
mentary eyes,  the  other  living  in  shallow  water 
and  with  the  eyes  well  developed.  An  interesting 
feature  of  this  case  was  that  the  practically  blind 
mother-crab  of  the  deep  water  wras  carrying  about 
larvae  with  darkly  pigmented  eyes,  showing  all  the 
essential  parts.  This  again  points  to  the  conclusion 
that  the  darkness  may  hinder  the  development  of 
the  eye  in  the  individual  lifetime.  In  other  words, 


PROBLEM  OF  CAVE  BLINDNESS      249 

the  rudimentariness  may  be  in  some  cases  imposed 
on  each  individual  generation,  and  the  result  of 
peculiarities  of  nurture  rather  than  of  hereditary 
nature. 

This  is,  of  course,  a  matter  for  experiment,  and 
some  data  are  already  available.  Thus,  Ogneff 
kept  goldfishes  for  three  years  in  absolute  darkness, 
taking  care  to  give  them  plenty  of  room  and  plenty 
of  food.  The  result  was  total  blindness;  even  the 
rods  and  cones  of  the  retina  disappeared.  We  may 
suppose,  then,  that  if  some  goldfishes  were  washed 
into  a  cave,  they  might  become  blind.  It  is  likely 
enough  too  (it  ought  to  be  tried)  that  their  offspring 
would  show  even  greater  degeneration  of  the  eye, 
being  exposed  to  darkness  from  birth.  If  the 
degeneration  of  the  eye  continued  to  increase  after 
the  second  generation  (and  this  also  should  be 
tested),  a  case  would  be  forthcoming  in  support  of 
the  theory  that  individually  acquired  modifications 
may  become  in  some  measure  part  of  the  inherit- 
ance. But  the  evidence  of  this  is  not  as  yet 
forthcoming,  and  OgnefFs  experiment  should  be 
repeated  by  other  experimenters  and  on  other 
fishes. 

It  is  a  very  instructive  fact  that  the  wan  Proteus 
from  the  caves,  which  shows  no  pigment  in  its  skin, 
becomes  rapidly  spotty  and  then  dark-colored  when 
brought  into  the  light.  It  responds  like  a  photo- 
graphic plate,  and  the  eggs  produced  in  the  light 
develop  into  dark-colored  offspring.  How  slow 
one  should  be  to  infer  the  absence  of  a  potentiality 


250  SECRETS  OF  ANIMAL  LITE 

from  the  fact  that  it  finds  no  bodily  expression  in  an 
unnatural  environment! 

But  without  excluding  the  possibility  that  the 
darkness  and  also  the  short  commons  of  caves  may 
have  some  effect  on  the  development  of  the  eye  in 
the  individual  lifetime,  we  cannot  believe  that  this 
is  more  than  a  side-issue.  We  must  remember,  for 
instance,  that  mammals  begin  their  life  in  an 
environment  of  complete  darkness  and  dwell  there 
often  for  many  months — in  the  case  of  the  elephant 
for  more  than  a  year.  Yet  this  has  no  prejudicial 
effect  on  the  development  of  the  eyes.  Not  long 
ago  Professor  Jacques  Loeb  made  the  simple 
experiment  of  rearing  embryos  of  a  minnow-like 
fish  (a  species  of  Fundulus)  in  an  absolutely  dark 
room,  but  no  trace  of  blindness  was  observed  after 
a  month.  This  result  is  the  more  interesting 
because,  as  we  shall  see,  it  is  very  easy  in  the  case 
of  this  fish  to  produce  blind  embryos  by  experi- 
mental methods.  But  not  by  darkness!  There 
are  many  other  difficulties  in  the  way  of  the  theory 
(which  Darwin  accepted)  that  the  cave-blindness  is 
the  hereditary  result  of  atrophy  of  the  eye,  incident 
on  disuse  and  dwelling  in  darkness.  Professor 
Eigenmann,  who  has  made  a  special  study  of  cave- 
fishes,  thinks  that  living  in  darkness  tends  at  least 
to  increase  the  optic  degeneration,  but  he  calls 
attention  to  the  difficulty  that  of  the  four  kinds  of 
salamander  living  habitually  in  North  American 
caves,  two  have  quite  degenerate  eyes  and  two  have 
them  normal.  But  what  is  sauce  for  the  goose 


PROBLEM  OF  CAVE  BLINDNESS      251 

should  serve  also  for  the  gander.  Some  cave  animals 
have  normal  eyes,  and  a  few  animals  that  live  in  the 
open,  like  the  shore-fish  Typhlogobius,  are  blind. 

What  is  the  other  theory?  Simply  that  the 
blindness  arose  as  a  germinal  variation  or  muta- 
tion, and  that  it  suited  cave-life.  For  a  useless 
organ  is  a  weak  spot.  On  this  view  there  is  no 
difficulty  in  the  rarity  of  rudimentary  eyes  in  open- 
air  conditions,  for  variations  in  an  obviously  dis- 
advantageous direction  tend  to  be  eliminated.  The 
difficulty  is  rather  in  finding  facts  to  justify  the 
belief  that  the  occurrence  of  variations  in  the 
direction  of  blindness  may  be  postulated  with  some 
show  of  reasonableness.  It  is  here  that  the  recent 
work  of  Loeb  comes  in.  This  brilliant  experimenter 
of  the  Rockefeller  Institute  has  found  that  it  is 
quite  easy  to  produce  a  percentage  of  fish-embryos 
(Fundulus)  with  defective  eyes  (a)  by  unsuitable 
crossing,  (b)  by  adding  a  little  potassium  cyanide 
to  the  water,  or  (c)  by  exposing  the  developing  eggs 
to  very  low  temperatures.  It  is  not  suggested  that 
the  ancestors  of  the  blind  cave-animals  became 
blind  as  the  result  of  parental  mismating,  or  of 
poisoning,  or  of  great  cold;  what  the  experiments 
show  is  that  relatively  slight  external  changes  may 
so  alter  the  constitution  of  the  germ  that  a  leap  is 
taken  in  the  direction  of  blindness.  Therefore  in 
our  theory  of  the  origin  of  cave-blindness  it  is  quite 
legitimate  to  start  with  postulating  heritable 
germinal  mutations  which  we  cannot  definitely 
account  for.  On  this  view,  the  tendency  towards 


252  SECRETS  OF  ANIMAL  LIFE 

blindness  arose  independently  of  the  presence  or 
absence  of  light,  and  Loeb  finds  an  analogy  in  that 
hereditary  kind  of  human  blindness  which  is  called 
glaucoma  and  is  associated  with  atrophy  of  the 
optic  nerve. 

If  the  variations  in  the  direction  of  blindness 
occurred  long  ago  within  the  cave  itself,  then,  if 
the  creature  was  otherwise  adaptable,  a  blind  race 
might  arise.  But  what  if  the  variations  occurred 
in  the  open?  The  first  half  of  the  answer  is  that 
they  would  be  speedily  wiped  out  unless  they  took 
to  a  cryptozoic  mode  of  life;  for  blind  members 
of  an  eyed  race  would  be  severely  handicapped  in 
the  search  for  food  and  mates.  The  other  half  of 
the  answer  is  that  there  would  often  be  a  chance 
that  blindish  variants,  arising  in  the  open,  might 
find  their  way  into  the  asylum  of  caves,  where 
blindness  is  no  disadvantage.  In  this  connection 
there  is  great  interest  in  Eigenmann's  observation 
that  the  open- world  relatives  of  cave-animals  are 
constitutionally  light-avoiders  (i.e.  negatively  helio- 
tropic)  and  given  to  keeping  in  contact  with  solid 
bodies  (i.e.  positively  stereotropic).  Thus,  if  the 
variation  in  the  direction  of  blindness  did  not 
change  the  constitution,  the  variants  would  have  a 
tendency  to  move  into  caves. 

These  constitutional  proclivities  probably  count 
for  much,  but  we  cannot  believe  that  they  exhaust 
the  situation,  for  we  see  all  around  us  in  the  realm 
of  organisms  illustrations  of  a  kind  of  behavior 
which  spells  endeavor  after  well-being.  Even  the 


PROBLEM  OF  CAVE  BLINDNESS      253 

blind  variant  will  go  on  proving  all  things,  and  it 
will  hold  fast  to  its  cave  if  it  gets  there.  In  its 
automatic  elimination  of  the  relatively  unfit  the 
environment  does  in  a  metaphorical  sense  select 
organisms,  but  the  correlated  fact  is  that  organisms 
seem  often  quite  literally  to  select  their  environ- 
ment. Just  as  an  animal  with  well-developed  eyes 
will  try  to  get  out  of  the  cave  into  which  it  has  been 
washed,  so  a  blind  animal  arising  as  a  variant  in 
the  open  may  actively  grope  its  way  in. 


XXXIII 
CONVERGENCE  IN  EVOLUTION 

IN  the  darkness  of  the  Deep  Sea  there  are 
certain  fishes  whose  eyes  have  dwindled  to 
a  vanishing-point.  By  means  of  delicate  tactile 
organs  they  feel  their  way  about  on  the  sea  floor. 
There  are  other  abyssal  fishes  with  enormously 
enlarged  eyes,  and  it  is  reasonably  supposed  that 
they  are  able  to  profit  by  the  faint  illumination 
due  to  "  phosphorescent  "  deep-sea  animals.  Yet  a 
third  condition  is  seen  in  a  number  of  fishes  from 
great  depths  in  which  the  eyes  are  elongated  into 
cylinders,  projecting  like  opera-glasses  on  the  top 
of  the  head.  These  have  been  called  "  telescope 
eyes,"  and  they  are  adapted  to  make  the  most  of 
faint  light.  The  lens  is  relatively  large,  and  the 
distance  between  it  and  the  surface  of  the  retina,  on 
which  the  image  is  formed,  is  much  greater  than 
usual.  Something  of  the  same  sort  is  seen  in  the 
eyes  of  owls,  though  they  do  not  project  in  the  same 
way.  For  the  sake  of  simplicity  let  us  leave  the 
owls  and  two  or  three  similar  instances  out  of 
account,  and  focus  attention  on  the  fact  that  the 
"  telescope  eyes "  of  some  deep-sea  fishes  are 
closely  paralleled  by  "telescope  eyes"  in  some 
deep-sea  cuttlefishes,  which,  of  course,  are  mollusks. 

254 


CONVERGENCE  IN  EVOLUTION       255 

This  illustrates  what  is  called  convergence,  the 
occurrence  of  similar  adaptations  to  similar  con- 
ditions in  two  sets  of  animals  not  even  distantly 
related.  Fishes  and  cuttlefishes  are  on  entirely 
different  lines  of  evolution;  moreover,  the  in- 
dividual development  of  the  eye  is  radically  different 
in  the  two  cases;  yet  both  may  show  telescope 
eyes.  Weismann  defined  convergence  as  "  corre- 
sponding adaptations  to  similar  conditions  in  ani- 
mal forms  not  genealogically  connected  with  one 
another";  and,  in  addition  to  the  unrelatedness  of 
fish  and  cephalopod,  he  pointed  out  that  the  fishes 
with  telescope  eyes  could  not  be  regarded  as  the 
descendants  of  a  single  ancestral  species  which 
achieved  the  remarkable  adaptation.  It  seems 
rather  that,  even  within  the  class  of  fishes,  telescope 
eyes  have  arisen  independently  several  times  over. 
Similarly  it  may  be  noticed  that  the  adaptation  of 
pectoral  fins  as  volplanes  must  have  occurred  inde- 
pendently in  two  distinct  sets  of  fishes,  and  that  the 
transformation  of  muscular  tissue  into  an  electric 
organ  must  have  occurred  independently,  at  least 
twice,  namely,  in  the  Torpedo  type  and  the  Gym- 
notus  type,  while  that  of  the  African  catfish  is  on  a 
different  line,  being  transformed  glandular  tissue. 
Very  much  the  same  as  "  convergence  "  is  the  term 
"  homoplasy,"  which  Sir  Ray  Lankester  used  for 
similarity  of  form  in  types  of  quite  different  pedi- 
gree. It  is  important  for  clear  thinking  to  dis- 
tinguish convergent  or  homoplastic  resemblance 
from  homology,  which  means  sameness  in  funda- 


256  SECRETS  OF  ANIMAL  LIFE 

mental  architecture  and  mode  of  development,  and 
is  always  an  indication  of  blood  relationship,  either 
near  or  remote.  The  only  readily  available  dis- 
cussion of  convergence  is  Professor  Arthur  Willey's 
important  essay  Convergence  in  Evolution  (1911), 
from  which  we  have  taken  several  illustrations. 

Queerest  of  queer  fishes  is  the  sea-horse,  Hippo- 
campus, often  seen  in  aquaria,  which  hangs  itself 
from,  or  supports  itself  on,  seaweeds  by  means  of 
a  prehensile  tail,  which  moves  dorsoventrally,  not 
laterally,  as  in  other  fishes.  It  has  a  rapidly 
vibrating  unpaired  fin  on  its  back,  and  the  peculiarity 
of  rolling  its  large  eyes  independently  of  one  an- 
other. Now,  it  is  curious  that  the  far-removed 
chameleon,  which  is  a  quaint  arboreal  lizard,  should 
show  the  same  sort  of  prehensile  tail  as  the  sea- 
horse, only  more  so,  and  the  same  independent  roll- 
ing of  the  eyes.  But,  as  Professor  Willey  points 
out,  the  pipe-fishes,  which  are  related  to  the  sea- 
horse, but  have  not  prehensile  tails,  also  show  inde- 
pendently rolling  eyes.  Therefore  the  association  of 
separately  moving  eyes  and  prehensile  tail  is  rather 
a  coincidence.  The  significance  of  the  mobile  eyes 
is  in  relation  to  the  sluggish  habits  and  the  relative 
inflexibility  of  the  body  in  sea-horse  and  chameleon 
alike. 

Take  another  example.  With  the  exception  of 
the  American  opossums  and  selvas,  all  living 
marsupials  (pouched  mammals)  are  natives  of 
Australasia,  where,  by  a  geological  change,  their 
ancestors  were  insulated,  and  thus  left  to  evolve 


CONVERGENCE  IN  EVOLUTION       257 

by  themselves  apart  from  other  mammals.  Now, 
it  seems  at  first  sight  very  remarkable  that  the 
marsupials  should,  in  the  course  of  time,  have 
come  to  present  what  may  be  called  superficial 
Duplicates  of  several  orders  of  the  higher  mammals. 
The  Tasmanian  wolf  converges  towards  a  true  wolf, 
the  banded  ant-eater  to  a  true  ant-eater,  the  flying 
phalanger  to  a  flying  squirrel,  the  swimming  yapock 
to  an  otter,  the  bandicoots  to  rats,  the  marsupial 
mole  to  a  true  mole,  and  so  on.  The  parallelism  is 
very  interesting,  for  marsupials  are  not  on  the  same 
line  as  placental  mammals;  yet  one  is  perhaps 
inclined  to  make  too  much  of  it.  It  must  be  remem- 
bered that  the  different  kinds  of  habitat  and  the 
different  ways  of  getting  a  livelihood  that  are  open 
to  mammals  are  not  very  numerous,  and  that  Nature 
was  therefore  almost  bound  to  repeat  herself.  In 
the  same  way  it  is  not  surprising  that  there  should 
have  been  terrestrial,  aquatic,  and  aerial  reptiles 
in  Mesozoic  ages,  just  as  there  are  terrestrial, 
aquatic,  and  aerial  mammals  to-day.  Some  good 
cases  of  convergence  occur  between  rodents  and 
insectivores,  e.g.,  between  mouse  and  shrew,  porcu- 
pine and  hedgehog,  squirrel  and  tree-shrew;  but 
we  have  given  illustrations  enough.  The  climax 
is  to  be  found  in  the  "  mimicry  "  of  unrelated  types, 
but  this  problem  is  better  kept  apart,  since  the 
superficial  resemblance  in  itself  is  here  of  survival- 
value  and  may  be  the  direct  result  of  natural 
selection. 

In  his  Creative  Evolution  Professor  Bergson  dealt 


258          SECRETS  OF  ANIMAL  LIFE 

at  some  length  with  the  resemblance  between  the 
scallop's  eye  and  the  vertebrate's  eye,  pointing  out 
the  difficulties  in  interpreting  this  in  terms  of  the 
selection  of  accidental  variations  either  insensible 
or  considerable  in  amount,  or  in  terms  of  an  inter- 
action of  internal  and  external  forces,  or  in  terms  of 
use-inheritance.  Without  denying  that  each  of  these 
theories  may  be  "  true  in  its  way,"  he  argued  that 
it  was  necessary  to  supplement  them  by  the  idea 
of  a  common  "  original  impetus/'  which  is  the 
fundamental  cause  of  heritable  variations.  But  Pro- 
fessor Bergson  unfortunately  exaggerated  the  re- 
semblance between  the  eye  of  the  backboned  animal 
and  the  "eye"  of  the  scallop;  except  the  "in- 
version of  the  retina  "  they  have  little  in  common. 
Moreover,  the  scallop's  numerous  eyes  may  not 
be  eyes  at  all,  in  the  strict  sense.  We  do  not  think 
that  Professor  Bergson  did  justice  to  the  subtlety 
of  even  the  orthodox  Darwinian  position,  or  to 
the  facts  which  have  saved  the  neo-Darwinian,  at 
least,  from  being  shut  up  to  a  belief  in  "  accidental  " 
variations,  or  the  role  that  the  organism  plays 
as  a  genuine  agent  in  testing  its  germinal  variations 
in  reference  to  environing  conditions  which  it  has 
a  share  in  selecting.  But  we  think  he  was  right  in 
thinking  that  the  interpretation  of  convergence  is 
not  altogether  plain  sailing. 

If  one  plays  long  enough  with  cards  one  will 
repeat  identical  hands,  and  if  a  certain  type  of 
structure  is  the  only  one  adapted  to  certain  circum- 
stances, or  is  far  and  away  fitter  than  any  other 


CONVERGENCE  IN  EVOLUTION       259 

type  of  structure,  we  can  theoretically  suppose 
that  it  will  be  reached  in  the  course  of  time  by  the 
selection  of  variations,  along  two  or  more  distinct 
routes.  In  some  cases,  however,  it  is  an  assumption 
to  say  that  the  type  of  structure  attained  is  the 
only  possible  solution  of  the  problem,  or  by  far 
the  best  and  easiest.  Moreover,  the  difficulty  of 
Darwinian  interpretation  increases  a  little  when  the 
mode  of  individual  development  is  quite  different  in 
the  two  cases,  and  when  the  similarities  include 
minute  details.  The  striking  superficial  resemblance 
between  burrowing  amphibian,  burrowing  lizard, 
and  burrowing  snake — a  familiar  puzzle  to  students 
of  elementary  zoology — is  readily  intelligible,  for 
the  worm-like  shape  is  the  only  one  possible;  but 
is  there  not  more  difficulty  in  accounting  for  the 
telescope  eyes  of  unrelated  fishes  and  cuttlefishes, 
where  the  general  idea  is  the  same,  though  there 
are  marked  differences  in  deail  and  in  development? 
Some  thoughtful  students  of  evolution *  see  no 
special  riddle  in  the  attainment  of  closely  similar 
adaptations  by  unrelated  types.  But  as  we  do  not 
regard  with  much  satisfaction  or  confidence  the 
available  biological  interpretations  of  the  way  in 
which  creatures  of  very  diverse  flesh  and  blood 
have  often  worked  out  the  same  solution  to 
a  problem,  we  would  make  three  suggestions. 
( i )  There  are  probably  architectural  laws  of  growth 
and  differentiation  of  which  we  have  not  more  than 

1  See  for  a  clear-headed  discussion  a  letter  by  Mr.  George 
Hookham  in  The  New  Statesman,  6th  Jan.,  1917,  p.  325. 


-260  SECRETS  OF  ANIMAL  LIFE 

glimpses.  Thus  the  very  frequent  recurrence  of  a 
logarithmic  spiral — in  shell  and  horn,  in  intestine 
and  cochlea — probably  expresses  a  deep-seated 
growth-necessity.  (2)  Many  an  organ  that  looks 
at  first  sight  complicated,  say  the  pancreas  or 
sweetbread,  consists  of  the  endless  repetition  of 
the  same  little  structure-unit,  consisting  of  groups 
of  cells  and  the  like.  Some  of  these  structure-units 
are  very  definite  and  have  probably  formed  part  of 
the  common  inheritance  of  more  than  one  great 
series  of  animals,  now  attaining  prominent  expres- 
sion and  again  sinking  into  insignificance,  but  never 
lost  from  the  racial  currency.  Thus  it  may  well  be 
that  the  structural  units  of  the  sensory  lateral  line  of 
most  fishes  are  really  the  same  as  the  lateral  sense- 
organs  of  certain  marine  worms  known  as  Capitel- 
lids.  "  In  both  cases/*  Professor  Willey  writes, 
"  the  essential  organs  consist  of  small,  solid,  round- 
ish, epidermal  buds,  from  which  stiff  sense-hairs 
project  freely  into  the  surrounding  medium;  and  the 
resemblance  is  further  enhanced  by  their  segmental 
arrangement.  The  correspondence  could  hardly  be 
greater,  the  convergence  could  hardly  be  closer, 
the  homology  could  not  be  more  remote  than 
infinity."  It  may  be,  however,  that  we  have  here 
to  do  not  with  Nature  repeating  herself,  but  with 
the  conservative  persistence  of  a  well-defined 
structure-unit,  or  "  morphon,"  as  it  has  been  called. 
(3)  Every  art  is  limited  by  its  medium,  and  so  is 
organic  evolution.  We  must  not  think  of  an  animal 
having  carte  blanche  in  its  morphogenic  speculations. 


CONVERGENCE  IN  EVOLUTION       261 

It  is  limited  in  its  acquisitions  by  what  has  been 
already  established,  just  as  an  architect  in  making 
an  addition  to  a  house  is  limited  by  the  existing 
style.  Flying  birds  differ  greatly  in  detail,  but 
within  a  relatively  narrow  range.  No  mutation 
can  be  considered,  so  to  speak,  which  risks  a  loss 
of  the  secret  of  flight.  Along  this  line  of  thought 
we  may  get  another  gleam  of  light  on  convergence. 
Other  solutions  than  that  adopted  are  possible  to  a 
theoretical  organism,  but  not  to  this  or  that  par- 
ticular organism  which  has  to  run  in  the  trammels 
of  a  hereditary  organization.  Why  should  all  the 
ordinary  mammals  of  our  acquaintance  be  restricted 
to  four  legs?  The  dachshund  often  looks  as  if  it 
could  do  with  another  pair  about  half-way  along, 
and  so  does  a  sow — also  a  somewhat  artificial 
creature.  The  proposition  of  an  extra  pair  cannot 
be  considered,  however,  for  higher  vertebrates  are 
hereditarily  tied  down  to  a  maximum  of  two  pairs  of 
limb-buds,  just  as  they  probably  are  to  a  maximum 
of  twelve  cranial  nerves,  where  an  increase  would  be 
more  readily  effected.  It  is  interesting,  however, 
to  force  the  question  back  and  ask  why  some  of  the 
lower  vertebrates,  notably  fishes,  might  not  have 
tried  the  experiment  of  an  additional  pair  of  limbs. 
In  all  probability  the  answer  is  simple :  that  paired 
limbs  were  established  at  the  level  of  fishes,  and 
that  their  primary  function  was  in  connection  with 
balancing,  not  with  locomotion,  the  locomotor 
organ  in  almost  all  fishes  being  the  so-called  tail. 
Now,  for  balancing  purposes  the  choice  is  between 


262  SECRETS  OF  ANIMAL  LIFE 

one  pair  and  two  pairs.  The  evolution  of  a  third 
pair  of  balancers  would  mean  an  increase  in  the 
functional  problem  of  correlation  without  any 
corresponding  advantage  in  the  way  of  efficiency, 
John  Burroughs  writes  somewhere  about  the  gain 
it  would  be  if  we  could  open  one  pair  of  eyes  after 
another  and  thus  see  more  of  the  wonder  of  Nature. 
The  probability  is  that  we  should  see  less,  for  the 
difficulty  of  correlating  impressions  would  be  insur- 
mountable. It  is  significant  that  those  backboneless 
animals  that  have  many  eyes  have  little  vision,  and 
that  the  unpaired,  median,  upward-looking,  pineal 
eye  which  some  backboned  animals  possessed  has 
not  been  retained  as  an  eye  in  higher  types.  It 
may  be,  then,  that  limits  imposed  by  growth-neces- 
sities, by  the  persistence  of  well-defined  structure- 
units,  and  by  pre-existing  organization  may  throw 
some  additional  light  on  the  fact  of  convergence. 


XXXIV 
DOES  ACQUIRED  VIGOR  COUNT? 

IN  ordinary  talk  we  often  hear  of  a  mysterious 
quality  called  vigor,  but  it  is  very  rarely  that 
any  one  even  asks  for  a  definition.  It  is  evidently 
something  more  than  strength,  for  men  with 
powerful  thews  and  sinews  are  often  far  from 
vigorous;  it  is  something  more  than  health,  for  a 
centenarian  sea-anemone  cannot  be  called  vigorous. 
The  quality  seems  to  mean  capacity  for  living 
intensely,  yet  without  any  loss  of  balance,  a  power 
of  expending  energy  lavishly,  yet  without  ceasing 
to  have  plenty  in  reserve,  an  ability  to  resist  strain 
and  to  defy  fatigue.  It  implies  being  ever  ready 
for  great  exertions,  and  yet  having  staying  power. 
It  must  depend  in  part  on  an  harmonious  adjust- 
ment of  the  various  functions  of  the  body,  including 
those  of  internal  secretion  and  those  which  keep 
the  wheels,  so  to  speak,  of  the  body-mind  or  mind- 
body  from  becoming  either  clogged  or  rusty. 
Probably  it  expresses  a  certain  perfection  in  the 
characteristic  quality  which  living  creatures — in 
contrast  to  inanimate  systems — have  of  circum- 
venting the  second  law  of  thermo-dynamics — of  at 
least  delaying  the  tendency  that  energy  has  in  its 
transformations  to  pass  into  unavailable  form.  We 

203 


264  SECRETS  OF  ANIMAL  LIFE 

have  dwelt  on  this  popular  concept  of  vigor  not 
because  we  are  confident  we  know  what  vigor 
precisely  is,  but  because  we  are  convinced  that  it 
means  more  than  is  indicated  in  a  recent  work  of 
considerable  interest  which  bears  the  title  Vigor 
and  Heredity.1  According  to  the  author,  Mr.  J. 
Lewis  Bonhote,  well  known  as  an  experienced  orni- 
thologist, vigor  may  be  defined  as  "  activity  of 
nutrition  and  function/'  or  as  "  rate  of  metabolism/' 
It  is  not  so  much  like  heat  as  like  temperature;  and 
it  requires  to  be  qualified  by  some  adjective,  as 
"  high  vigor/'  or  "  low  vigor."  It  is  the  rate  of 
metabolism.  Now  "metabolism"  is  just  a  con- 
venient general  term  for  the  manifold  complex 
chemical  processes  which  go  on  in  a  living  body, 
some  of  them  of  a  constructive,  synthetic,  upbuild- 
ing, or  assimilative  character  (anabolic),  and  others 
of  a  disruptive,  analytic,  down-breaking  or  disas- 
similative  character  (katabolic).  But  it  is  a  very 
wide  term  and  includes  such  a  variety  of  processes 
that  "  the  rate  of  metabolism  "  does  not  mean  very 
much.  Two  creatures  may  have  the  same  number 
of  chemical  transactions  per  hour,  and  yet  have 
very  little  in  common  from  a  physiological  point  of 
view,  just  as  two  shops  may  have  the  same  number 
of  sales  in  a  day  and  yet  have  very  little  in  common 
commercially.  And,  again,  if  we  measure  the 
amount  of  metabolism  that  goes  on  in  a  day  in 
various  types  by  the  amount  of  oxygen  used  up,  or 

1  Vigor  and  Heredity.    By  J.  Lewis  Bonhote.    West,  New- 
man &  Co,  1915. 


DOES  ACQUIRED  VIGOR  COUNT?     265 

by  the  amount  of  carbon  dioxide  given  off,  or  by  the 
heat  evolved,  the  mere  fact  that  there  is  equality 
in  the  amount  of  metabolism  per  day  or  per  hour 
in  a  number  of  creatures  does  not  seem  to  tell  us 
much.  We  wish  to  know  the  nature  of  the  meta- 
bolism in  each  case,  for  it  is  not  a  matter  of  indiffer- 
ence whether  the  metabolism  is  mainly  concerned 
with  proteids  or  with  carbohydrates.  Once  again, 
a  given  animal,  such  as  a  midge,  might  have  intense 
metabolism  for  one  glorious  hour  of  crowded  life 
and  a  sluggish  metabolism  for  twenty-three  hours, 
and  yet  have  its  total  metabolism  for  the  day  equal 
to  that  of  another  creature,  such  as  an  amoeba, 
which  had  a  constant  slow-going  metabolism  all 
the  time.  It  is  open  to  Mr.  Bonhote  or  any  one 
else  to  call  "  the  rate  of  metabolism  "  by  the  name 
"  vigor/'  but  we  do  not  think  it  means  very  much 
unless  the  nature  of  the  metabolism  be  defined. 
It  is  not  "  the  pace  "  merely  that  matters,  but  the 
direction  of  the  steps.  How  much  of  the  metabolism 
is  anabolic  and  how  much  is  katabolic;  how  much 
is  adding  to  the  working  capital  of  living  matter 
and  how  much  is  an  accumulation  of  reserve  stock 
that  cannot  be  realized  except  under  particular 
conditions?  These  and  many  similar  questions, 
must  be  faced  before  we  can  consent  to  call  the 
rate  of  metabolism  vigor. 

The  author  of  Vigor  and  Heredity  has  been 
observing  animals  all  his  life  and  making  breeding 
experiments  with  rats  and  mice,  cats  and  dogs, 
pigeons  and  poultry  for  fifteen  years,  and  he  has 


266          SECRETS  OF  ANIMAL  LIFE 

got  something  quite  definite  to  say — something  well 
deserving  to  be  thought  over — that  the  physiological 
condition  of  the  parents  at  the  time  of  re- 
production influences  the  next  generation.  What  is 
meant  is  not  that  two  hard-set,  thick-skinned,  tough- 
minded,  and  well-controlled  parents  are  likely  to 
have  children  after  their  own  image,  or  that  two 
slack,  thin-skinned,  flabby-minded,  and  feckless 
parents  are  likely  to  have  children  after  their  kind; 
for  this  would  simply  be  the  generally  accepted 
doctrine  that  innate  constitutional  characters  are 
entailed  from  generation  to  generation.  Like  tends 
to  beget  like ;  no  grapes  from  thorns  nor  figs  from 
thistles.  But  what  Mr.  Bonhote  means  is  something 
different  and  something  debatable. 

His  argument  is  this.  Changes  or  peculiarities  in 
environmental  conditions  (including  food,  warmth, 
humidity,  and  so  on)  have  an  influence  on  the 
physiological  state  of  susceptible  organisms.  Corre- 
sponding to  the  "  nurtural  "  changes  or  peculiarities 
there  are  often  internal  changes  in  the  metabolism. 
This  is  admitted  by  all  biologists.  But  may  it  not 
be  that  the  character  of  the  metabolism,  environ- 
mentally modified  about  the  time  of  parentage, 
reacts  on  the  germ-cells  and  affects  them  in  some 
way,  so  that  their  development,  i.e.  their  expression 
of  the  inheritance,  is  different  from  what  it  would 
have  been  if  the  parental  constitution  had  not  been 
affected  by  the  nurtural  modifications?  In  the 
author's  terminology,  which  we  cannot  accept,  the 
altered  vigor  of  the  parents  may  affect  the  initial 


DOES  ACQUIRED  VIGOR  COUNT?     267 

vigor  of  the  germ-cells,  and*  the  developmental 
vigor  of  particular  items  in  the  inheritance.  The 
evidence  brought  forward  in  support  of  this  view 
is  confessedly  indirect.  In  his  experience  as  a 
breeder  Mr.  Bonhote  has  been  puzzled  by  many  of 
his  results.  He  could  not  interpret  them  in  terms 
of  Mendelian,  Galtonian,  or  any  other  formulae,  but 
he  found  them  intelligible  on  the  theory  that  the 
physiological  condition  of  the  parents  at  the  time 
of  reproduction  may  influence  the  germ-cells  and 
their  development.  Low  vigor  in  the  parents  will 
tend  to  be  echoed  in  weakly  offspring;  high  vigor 
will  make  for  racial  stability.  But  what  is  required 
is  careful  and  skeptical  criticism  of  all  the  evidence 
that  points  to  the  conclusion  that  the  constitutional 
vigor,  or  vitality,  or  healthfulness  of  the  parents  at 
the  time  of  parentage  really  counts  in  the  devel- 
opment of  the  offspring.  This  is  a  momentous 
question,  not  to  be  answered  by  opinions,  or  on 
hearsay  evidence,  or  even  by  reference  to  particular 
observations,  such  as  the  often-noticed  delicacy  of 
the  children  of  a  more  or  less  invalided  and  worn- 
out  father.  In  the  case  of  Mammals  the  problem  is 
complicated  by  the  usually  prolonged  period  of 
intimate  symbiosis  between  the  mother  and  the 
offspring,  during  which  it  would  be  strange  indeed 
if  the  development  were  not  sometimes  perturbed 
when  there  are  profound  changes  in  the  maternal 
metabolism.  That  such  perturbations  are  not  more 
noticeable  is  largely  due  to  subtle  adaptations  which 
screen  the  young  life  from  harm. 


268          SECRETS  OF  ANIMAL  LIFE 

Mr.  Bonhote  is  not  much  concerned  with  the 
question  of  the  possible  transmission  of  individually 
acquired  bodily  modifications  due  to  peculiarities 
of,  or  changes  in,  function  and  environment;  his 
central  idea  is  that  the  physiological  state  of  the 
parent,  when  functioning  as  a  parent,  may  influence 
the  offspring.  There  is  abundant  experimental 
evidence  to  show  that  a  slight  change  in  the  chemical 
and  physical  medium  of  the  germ-cells  and  the 
early  embryonic  stages  may  have  a  profound  effect 
on  the  development.  To  a  degree  previously 
unsuspected,  appropriate  liberating  stimuli  are 
required  to  release  the  primordia  of  the  various 
organs  and  qualities.  And  there  are  inhibitors  as 
well  as  liberators.  Add  a  drop  from  one  philter 
and  the  embryo  will  be  blind,  from  another  and  it 
will  have  no  food-canal.  It  must  be  remembered, 
too,  that  much  depends  on  the  tempo  of  develop- 
ment, and  that  great  changes  may  be  brought  about 
by  accelerating  here  and  slowing  there.  In  this 
connection  our  author  might  have  found,  had  he 
known,  some  vindication  of  the  emphasis  which  he 
puts  on  "  the  rate  of  metabolism." 

To  make  Mr.  Bonhote's  point  quite  clear,  we 
must  emphasize  the  fact  that  he  is  not  merely  con- 
cerned with  the  conclusion  that  nurture  counts  for 
much  in  the  development  or  expression  of  the  indi- 
vidual's hereditary  nature;  his  suggestion  is  that 
nurture  goes  farther  back.  There  is  no  doubt  that 
appropriate  food  and  warmth  and  moisture  and  the 
like  may  conspire  to  heighten  the  vigor  of  the  parent 


DOES  ACQUIRED  VIGOR  COUNT?     269 

organisms;  the  hypothesis  is  that  this  is  reflected 
in  increased  initial  vigor  in  the  offspring.  Filled 
with  enthusiasm  for  this  theory — unproved  though 
it  be — Mr.  Bonhote  looks  forward  to  far-reaching 
effects  on  mankind  when  the  importance  of  nurture 
is  realized.  "  When  it  is  once  realized  that  char- 
acters may  be  largely  eliminated  by  environment, 
if  brought  to  bear  early  enough,  we  have  open  to  our 
vision  possibilities  far  greater  than  any  offered  by 
the  actual  work  of  Mendel."  This  much  of  quota- 
tion will  seem  to  many  so  profane  that  we  dare  not 
continue  it.  From  our  point  of  view  it  is  not  in 
any  way  profitable  to  pit  against  one  another  the 
correlated  concepts  of  "  nature "  and  "  nurture." 
We  believe  that  any  nurture  which  contributes  to 
the  development  of  vigor  in  the  sense  indicated 
in  the  beginning  of  this  article  must  be  progressive, 
and  that  it  cannot  begin  too  soon,  since  it  is  an 
individual  reward  in  itself,  apart  from  any  off- 
chance  of  influencing  offspring. 

We  know  experimentally  that  germ-cells  in  the 
body  of  the  parent  organism  may  be  in  a  general 
way  deteriorated  by  various  influences,  such  as 
those  of  radium  or  alcohol.  But  we  know  also  that 
it  is  scientifically  dangerous  to  argue  from  Rotifer 
to  Man,  even  from  Guinea-pig  to  Man.  What  is 
certain,  however,  is  that  the  vigor  of  the  mother 
during  the  time  of  ante-natal  symbiosis  with  her 
child  is  of  far-reaching  importance. 


XXXV 
THE  UNSEEN  GOAL 

^  I  ^  HAT  one  swiftly  moving  battleship  should 
J_  sink  another  from  a  distance  of  many 
miles — the  victim  being  to  ordinary  eyes  invisible 
— seems  a  wonderful  achievement,  and  not  less  is 
the  triumph  of  hitting  a  mark  outside  the  range 
of  direct  observation.  We  know  nothing  of  the 
problems  of  this  fell  gunnery;  we  are  concerned 
with  what  seems  even  more  difficult  to  understand 
— the  way  in  which  animals  often  work  persistently 
and  elaborately  towards  an  unseen  goal. 

To  take  a  typical  illustration:  many  of  the 
digger-wasps  make  burrows  in  the  ground,  in  which 
they  lay  their  eggs  and  also  collect  a  store  of 
paralyzed  insects — a  living  larder  for  the  future 
grubs.  But  it  is  only  in  a  few  species  that  the 
hard-working  mothers  survive  to  see  their  offspring. 
So  the  puzzle  arises:  How  can  the  elaborate  in- 
stinctive behavior  have  been  evolved?  We  see 
a  concatenation  of  intricate  dexterities  resolutely 
persisted  in:  the  stinging  of  the  victim  so  that  it  is 
paralyzed,  yet  not  a  corpse  that  would  decay;  the 
transport  of  the  booty  to  the  burrow — a  task  often 
requiring  prodigious  exertions;  the  placing  of  egg 
and  provender  in  proper  juxtaposition;  the  exclu- 

270 


THE  UNSEEN  GOAL  271 

sion  of  possible  intruders;  and  so  on.  It  is  no 
simple  performance  but  a  whole  bag  of  tricks.  The 
sequence  is  quite  intelligible  to  us  who  see  the  end; 
but  has  the  succession  of  events — often  requiring 
toil  and  trouble — any  significance  to  the  performers  ? 
If  it  has  no  significance,  how  then  did  it  evolve 
and  why  is  it  persisted  in?  If  it  has  significance, 
how  is  that  gained  if  the  performers  do  not  see  the 
result  of  their  labors? 

Some  of  those  who  have  thought  over  this  prob- 
lem have  pointed  to  men  who  spend  themselves 
in  working  towards  achievements  which  cannot  be 
realized  in  their  day  and  generation.  But  the 
analogy  does  not  help  us,  for  the  cathedral  of 
Burgos,  or  the  great  afforestation,  or  the  Chinese 
Encyclopaedia  is  completed  as  an  ideal  in  the  minds 
of  the  human  workers  and  is  built  up  of  elements 
previously  actualized  in  experience.  But  the  digger- 
wasps  have  had  no  experience  bearing  upon  off- 
spring. It  is  said  that  beavers  sometimes  dig  a 
short-cut  canal  right  through  a  large  island  amid- 
stream,  thus  lessening  the  distance  for  transporting 
"  logs,"  and  such  a  task  must  engage  the  energies 
of  the  workers  for  a  long  time  before  there  is  any 
reward.  For  the  canal  does  not  justify  itself  until 
it  is  open  at  both  ends.  But  such  a  case  is  not 
enigmatical  like  that  of  our  insects,  since  making  the 
island-canal  is  but  an  interesting  extension  of  the 
kind  of  labor  that  finds  immediate  justification 
in  the  everyday  life  of  the  beaver. 

Part  of  the  answer  to  the  riddle  is  to  be  found 


272          SECRETS  OF  ANIMAL  LIFE 

in  considering  the  maternal  care  of  some  of  the 
worker-ants  and  worker-bees,  who  are  normally 
non-productive  females.  They  mother  the  young 
as  if  these  were  their  own,  and  we  explain  this  by 
the  natural  supposition  that  this  capacity  dates 
back  to  the  time  when  all  the  females  were  normally 
mothers,  before  the  communal  life  with  its  marked 
division  of  labor  was  established.  It  may  be  re- 
membered that  fertile  workers  occasionally  occur, 
and  that  a  worker  grub  can  be  nurtured  into  a 
queen.  We  cannot  suppose  that  the  workers  simply 
inherit  their  nursing  capacities  from  their  mother 
— the  queen — for  she  does  not  exhibit  the  qualities 
required,  being  specialized  for  sheer  maternity.  We 
must  go  much  farther  back.  Another  illustration 
of  our  argument  may  be  found  in  a  widely  different 
sphere — in  the  case  of  the  European  cuckoo.  In  a 
somewhat  elaborate  way  the  mother-bird  secures 
the  success  of  offspring  to  which  she  is  herself  a 
stranger.  Laying  her  egg  on  the  ground,  she  takes 
it  in  her  mouth,  flies  with  it  down  the  hedgerow, 
and  puts  it  into  the  selected  nest  of  a  foster-parent, 
and  thus  hits  an  unseen  mark.  The  existence  of 
other  kinds  of  cuckoo  which  show  less  perfect 
evasion  of  parental  duties  convinces  us  that  the 
utilization  of  other  nests  and  of  foster-parents  was 
gradually  evolved  from  a  state  of  affairs  in  which 
cuckoos  reared  their  own  young.  The  egg  has 
significance  to  the  mother-cuckoo,  who  has  no 
experience  of  nestling  or  chick,  because  she  belongs 
to  a  race  in  which  brooding  was  once  the  rule. 


THE  UNSEEN  GOAL  273 

Similarly,  the  digger-wasp  that  shows  elaborate 
parental  care,  securing  the  safety  and  success  of 
young  which  are  never  seen,  does  so  because  it 
belongs  to  a  race  in  which  rearing  the  young  and 
perhaps  enjoying  their  company  was  long  ago  the 
rule.  The  internal  voice  that  the  creature  obeys 
is  the  reverberation  of  a  distant  past. 

When  we  try  to  picture  the  establishment  of  an 
instinctive  routine  we  naturally  think  of  the  creature 
wrinkling  its  brows  from  step  to  step,  and  from 
generation  to  generation  deliberately  introducing 
little  improvements,  until  the  behavior  becomes 
at  length,  like  a  patent,  extraordinarily  perfect. 
We  naturally  picture  the  process  in  this  way,  for 
it  is  thus  that  we  improve  on  our  manipulations. 
Now  without  denying  that  animals  of  the  small- 
brained  instinctive  type  may  better  their  behavior 
by  individual  improvements,  more  or  less  intelli- 
gent, we  cannot  believe  that  it  was  in  this  way  that 
instinctive  behavior  became  established.  Who, 
indeed,  shall  dogmatize  as  to  the  impossibility  of 
individual  experiences  affecting  the  entailed  in- 
heritance of  the  race,  or  set  limits  to  the  "  mysterious 
wireless  telegraphy  of  ante-natal  life";  but  it  does 
not  seem  likely  that  instinctive  behavior  is  in 
any  direct  way  due  to  the  transmission  of  the  results 
of  the  experiments  made  by  the  individual.  Often, 
for  instance,  a  very  effective  piece  of  behavior 
is  performed  only  once  in  a  lifetime,  which  does 
not  give  much  opportunity  for  heritable  imprinting. 
Often,  again,  the  behavior  is  connected  with  the 


274  SECRETS  OF  ANIMAL  LIFE 

origin  of  new  lives  and  is  not  justified  to  the  creature 
until  the  offspring  appear,  so  that  it  is  only  in 
animals  that  have  more  than  one  set  of  offspring 
that  the  organic  testimony  of  the  success  of  the  ex- 
periment could  be  transmitted.  Many  insects  and 
the  like  are  annuals  and  die  after  parentage.  With- 
out shutting  the  door  on  what  are  called  "  mnemic  " 
theories,  we  are  forced  by  the  difficulties  they  in- 
volve to  the  other  main  theory  of  the  racial  estab- 
lishment of  instinctive  routine.  On  this  view  the 
steps  that  count  are  made  in  the  dark  studio  of  the 
germ-plasm.  The  germ-cell,  an  organism  not  in 
miniature  so  much  as  in  microcosm,  is  the  real 
inventor,  the  creative  genius.  We  think  too  much, 
perhaps,  of  the  explicit  individual,  too  little  of  the 
implicit  individuality — the  germ-cell.  Not  to  be 
thought  of,  we  must  remember,  as  like  a  white 
blood  corpuscle,  but  rather  like  a  Proteus  animalcule 
that  has  been  living  on  for  millions  of  years,  experi- 
menting all  the  time  and  garnering  the  capacity  of 
repeating  what  was  successful.  It  has  withal  the 
power  of  including  with  its  own  experiments  in  self- 
expression  those  of  another  germ-cell  at  the  be- 
ginning of  each  new  life.  The  germ-cells  are  the 
blind-artists  of  the  realm  of  organisms,  ever  fashion- 
ing some  new  germinal  intricacy  which  finds  ex- 
pression in  some  novelty  of  structure  or  habit. 
And  on  this  view  the  individual,  in  which  the  germ- 
cell's  many  inventions  are  expressed,  embodied,  and 
exercised,  may  be  thought  of  as  the  seeing  artist, 
beholding  the  work  of  the  germ-cell  and  either 


THE  UNSEEN  GOAL  275 

pronouncing  it,  in  the  light  of  the  success  it  brings, 
to  be  good,  or  cursing  it  effectively  by  sinking  with 
it  into  extinction.  For  there  are  variations  that 
kill,  being  pathological — the  germinal  artist  is  not 
always  quite  sane — as  well  as  variations  that  enrich 
and  make  for  progress. 

Four  saving-clauses  may  be  permitted.  We  must 
not  think  of  the  microcosmic  individuality  of  the 
germ-cell  in  any  wooden  or  one-sided  way.  We 
cannot  conceive  how  it  has  unified  in  its  pin's-head 
scope  the  long  results  of  time,  the  treasures  of  the 
ages ;  but  so  it  is.  We  do  not  understand  how  it  is 
not  merely  protoplasm,  but  a  daimon  as  well;  but 
so  it  is.  Secondly,  we  must  not  exaggerate  the 
difficulty  of  understanding  how  the  microcosmic 
individuality  can  make  experiments — materially 
regarded,  permutations  and  combinations  of  mole- 
cules— which  have  relevancy  in  relation  to  the  outer 
world  in  which  the  macrocosmic  individual  will  live 
and  work.  It  is  metaphorically  like  this,  that  within 
the  germ-cell  there  is  an  achitecture — ideally  re- 
garded, an  idea — which  represents  the  hereditary 
organization  and  has  stood  the  test  of  time.  Now, 
the  changes  that  can  be  profitably  made  in  this 
architecture  must  be  more  or  less  congruent  with 
the  already  established  style,  just  as  an  experiment 
in  our  thinking,  if  it  is  to  be  successful  and  to 
survive,  must  be  consonant  with  already  established 
truth.  Therefore  the  germ-cell's  initiatives,  though 
sometimes  fools'  experiments,  partake  but  little  of 
the  fortuitous. 


276          SECRETS  OF  ANIMAL  LIFE 

In  stating  a  case  for  the  blind  marksman,  whose 
bow  is  bent  in  a  direction  to  some  degree  determined 
by  the  past,  and  therefore  with  a  result  that  has  an 
illusory  suggestion  of  foresight,  we  do  not  for  a 
moment  under-appreciate  the  role  of  the  seeing 
artist,  the  explicit  individual,  with  all  its  wits  about 
it,  an  instinctive  or  intelligent  or  rational  agent 
with  no  end  of  experimental  power  on  a  higher  than 
germinal  level.  But  our  thesis  is  to  suggest  that 
especially  in  the  lower  reaches  of  life  it  is  the  blind 
marksman  who  oftenest  scores.  The  last  point  is 
this,  that,  while  we  are  probably  wrong  in  trying 
to  justify  the  ways  of  the  species  to  the  individual, 
it  seems  unlikely  that  an  elaborate  piece  of  in- 
stinctive routine  could  retain  its  impervious  inertia 
through  the  ages  unless  a  sop  were  offered  to  the 
individual's  interests  and  satisfactions.  So,  as 
Goethe  said,  Nature  gives  a  couple  of  draughts  from 
the  tankard  of  love  as  recompense  for  the  pains  of 
a  lifetime,  and  in  the  case  of  animals  that  do  not 
survive  to  see  the  offspring  towards  whose  welfare 
they  spend  themselves,  the  parental  instincts  may 
have  become  in  some  special  way  linked  on  to  the 
conjugal.  In  the  latter  the  life  of  the  creature  is 
stirred  to  its  greatest  depth  and  rises  to  its  greatest 
height.  Perhaps  the  maternal  sacrifice  and  the 
strivings  of  the  parents  towards  an  unseen  goal 
may  have  a  spice  of  individual  significance  in  the 
reverberations  of  conjugal  experiences,  and  perhaps 
even  in  ancestral  reminiscences  which  these  have 
reawakened.  Moreover,  since  repression  may  in- 


THE  UNSEEN  GOAL  277 

tensify  as  well  as  expression,  it  seems  quite  legi- 
timate to  suggest  that  worker-ants  and  worker-bees, 
for  instance,  may  find  some  compensation  for  their 
spinsterdom  in  their  generous  vicarious  mother- 
hood. And  apart  from  all  guesses,  the  interest- 
ing fact  has  now  been  established  for  some  wasps 
(as  we  have  already  noticed),  and  for  some  ants 
(as  Professor  Wheeler  has  recently  proved),  that 
nurses  and  mothers  alike  may  receive  from  the 
larvae  which  they  feed  and  tend  drops  of  an  elixir 
that  seems  to  serve  as  an  extraordinarily  stimu- 
lating encouragement  or  reward  on  the  path  of 
virtue. 


.     XXXVI 
BEFORE  THE  DAWN  OF  ART 

IN  a  recent  paper  in  the  Philosophical  Transac- 
tions of  the  Royal  Society  of  London  (1915), 
Mr.  Edward  Heron-Allen  describes  the  nature  of 
the  shells  in  some  of  the  Foraminifera  or  chalk- 
forming  animals,  and  propounds  the  theory  that 
we  cannot  ascribe  to  these  unicellular  creatures 
anything  short  of  "  intelligence."  We  need  not 
quarrel  over  words:  the  important  fact  which  this 
expert  observer  has  brought  to  light  is  that  these 
relatively  simple  animals  sometimes  exhibit  con- 
sistent selection  in  taking  to  themselves  the  materials 
used  in  shell-formation,  and  that  they  sometimes 
use  this  material  in  a  singularly  effective  manner. 
Most  of  the  Foraminifera  make  shells  of  lime,  which 
are  secreted  in  the  surface  layer  of  the  living  matter, 
and  are  often  of  thrilling  beauty.  Many  of  them, 
as  every  one  knows,  have  entered  very  considerably 
into  the  formation  of  chalk  clifTs — deposits  on  the 
floor  of  bygone  seas;  many  of  them  are  accumulat- 
ing to-day  as  Foramini feral  ooze  in  some  of  the 
great  oceanic  abysses.  The  calcareous  shells  are 
often  exquisite,  and  one  can  spend  days  of  joy 
lingering  over  the  beauty  feast  which  they  spread 
before  us.  Wheels  and  spirals,  globes  and  cones, 

278 


BEFORE  THE  DAWN  OF  ART        279 

fans  and  trumpets,  towers  and  cupolas — what  a 
wealth  of  form  there  is  among  these  atomies  with 
their  hundreds  of  different  species!  One  of  the 
many  interesting  features  is  that  certain  of  the 
shapes  point  forward  to  the  shells  of  Cephalopod 
and  Gasteropod  mollusks. 

The  lime  shells  of  Foraminifera  have  been  familiar 
for  many  generations,  and  no  one  has  pretended 
to  understand  them.  They  are  secreted — simply 
secreted ! — by  organless  individuals,  each  "  a  drop  of 
protoplasm  "  which  streams  out  into  the  water  in  a 
changeful  network  of  delicate  threads.  Some  salt 
of  lime  is  absorbed  from  the  sea  water;  it  passes 
through  the  plasmic  laboratory;  it  is  laid  down  as 
an  arabesque  of  translucent  marble.  That  is  all! 
We  cannot  explain  how  Globigerina  makes  its 
beautiful  shell  any  more  than  we  can  explain  how 
the  nightingale  makes  his  song  or  the  poet  his  epic. 
Indeed,  we  are  intellectually  farthest  from  any 
understanding  of  the  Globigerina's  poem. 

But  what  prompted  us  in  this  discussion  had  to 
do  not  with  calcareous  shells,  but  with  those  that 
are  built  up  of  extrinsic  particles  selected  from  the 
surroundings.  It  is  of  the  so-called  arenaceous 
Foraminifera  that  Mr.  Heron-Allen  has  such  won- 
derful things  to  tell  us,  and  it  is  obvious  at  once  that 
the  problem  is  here  more  accessible — that  is  to  say, 
more  readily  attacked — by  way  of  experiment,  such 
as  Mr.  Heron-Allen  has,  we  believe,  the  patience 
and  ingenuity  to  devise.  In  the  case  of  calcareous 
shells  the  material  that  is  taken  in  is  invisible;  its 


280          SECRETS  OF  ANIMAL  LIFE 

transformation  (if  any)  is  invisible;  all  that  we  do 
observe  is  the  rising  of  a  visible  and  tangible  edifice 
in  the  transparent  medium  of  the  Foraminifer's 
protoplasm.  But  the  arenaceous  forms  use  visible 
ready-made  building  materials,  and  make  of  them 
an  encasement.  This  is  sometimes  beautiful,  oftener 
perhaps  simply  quaint;  the  interest  centers  in  the 
selection  of  the  materials  and  in  the  effective 
architecture.  First  as  to  selection:  a  particular 
kind  of  Foraminifer  surrounded  by  an  embarrassing 
wealth  of  alternatives  will  have  none  of  them  save 
intact  sponge-spicules,  out  of  which  a  transparent 
test  is  built  up.  Another  kind  will  use  only  grains 
of  quartz,  and  a  third  flakes  of  mica.  What  ex- 
periment will  show  is  whether  this  particulate 
utilization  of  certain  materials  is  obligatory  or  facul- 
tative? Is  past  experience  so  enregistered  within 
the  cell  that  the  searching  living  threads  will  respond 
to  sponge-spicule  only  ?  Or  would  the  creature  take 
Echinoderm  fragments  in  default  of  anything 
else?  Quite  extraordinary  is  the  case  of  a  species 
of  Technitella  which  makes  its  test  of  Echinoderm 
plates,  and,  having  no  definite  oral  aperture, 
sends  its  living  threads  flowing  through  the  pores 
which  these  plates  possess.  How  interesting,  too, 
is  the  morsel  of  fact  that  one  type  that  makes 
a  shell  of  sponge-spicules  will  only  use  them 
intact,  while  another  type  will  only  use  them 
broken!  It  has  been  suggested  that  when  the 
materials  used  by  a  particular  type  are  all  of  the 
same  kind,  and  therefore  of  the  same  specific 


BEFORE  THE  DAWN  OF  ART        281 

gravity,  they  will  lie  at  the  same  level  in  the  ooze; 
and  so  it  may  be  in  some  cases.  But  that  this  is 
not  all  is  proved  by  individuals  which  make  the 
bulk  of  the  shell  of  microscopic  quartz  grains,  but 
interpolate  at  intervals  little  gems  of  garnet, 
magnetite,  and  perhaps  topaz. 

Speaking  of  a  Foraminifer  common  on  the  rocks 
of  the  Mixon  Beacon,  a  couple  of  miles  out  to  sea 
from  the  point  of  Selsey  Bill,  Mr.  Heron- Allen 
writes :  "  Among  the  shells  of  this  species,  the 
majority  of  which  are  neatly  constructed  in  the 
ordinary  way,  of  very  small  quartz  grains,  built 
together  with  a  brilliantly  white  or  deeply  ferrugi- 
nous cement  (which  gives  a  very  distinctive  color- 
ing to  the  shells),  frequent  specimens  are  found 
which  have  selected  and  built  into  their  shells  rela- 
tively large  fragments  of  these  gem  materials,  and 
though  even  I  would  shrink  from  suggesting  the  in- 
clusion among  the  higher  qualities  of  Foramini feral 
protoplasm  of  an  '  aesthetic  sense/  the  selection  of 
these  grains  of  markedly  higher  specific  gravity  by  a 
very  restricted  proportion  of  the  animals  of  this 
species  seems  to  me  to  be  exceedingly  significant.  It 
affords  a  parallel  to  the  instances  of  selection,  by  dif- 
ferent species  living  on  the  same  bottom,  and  sur- 
rounded by  the  same  materials,  of  entirely  different 
elements,  to  which  Lister  has  called  attention."  In 
contrast  to  a  shell  of  quartz  grains  we  may  mention 
that  of  a  species  of  Reophax — a  fragile  many- 
chambered  tube  built  of  infinitesimally  small  flakes 
qf  mica,  joined  at  their  extreme  margins  by  chitinous 


282          SECRETS  OF  ANIMAL  LIFE 

material.     When  the  animal  is  living  this  delicate 
covering  is  pliable  like  chain  armor. 

What  Mr.  Heron-Allen  is  bold  enough  to  call 
"  intelligence "  is  even  more  strikingly  exhibited 
by  the  effective  manner  in  which  some  of  the  shell- 
builders  use  their  materials.  Many  years  ago 
Canon  Norman  described  how  Tcchnitella  (i.e.  "  the 
little  workman")  builds  its  shell  of  fragments 
of  minute  sponge  needles,  "  laid  down  in  regular 
Order  side  by  side,  and  cemented  with  a  mortar 
composed  probably  of  the  finest  dust  of  quartz,  so 
that  the  whole  test  is  of  exquisite  snowy  whiteness." 
But  the  accidental  breakage  of  the  shell  of  a  species 
d:f  Technitella  revealed  to  Mr.  Heron-Allen  and  his 
slcilful  collaborator,  Mr.  Earland,  an  even  more 
striking  fact.  The  whole  shell -wall  consists  of  two 
distinct  layers  of  spicules,  an  outer  layer  with  their 
long  axis  parallel  to  that  of  the  test,  and  an  inner 
layer  at  right  angles  to  those  outside,  "  giving  as 
close  an  approximation  to  the  woof  and  warp  of  a 
textile  fabric  as  is  possible  with  a  rigid  non-flexible 
material  such  as  sponge-spicules."  When  we  re- 
member that  this  is  no  matter  of  "  organic  crystalliza- 
tion," but  the  result  of  placing  extraneous  materials, 
selectively  gathered,  in  a  definite  and  singularly 
effective  arrangement,  we  feel  that  we  are  approach- 
ing the  dawn  of  art.  It  is  obvious  that  by  the 
crossing  of  the  two  layers  of  spicules  "  the  strength 
and  resistance  of  the  test  to  strain  is  enormously 
increased."  In  some  cases  the  use  of  the  spicules 
is  probably  protective  against  the  attacks  of  minute 


BEFORE  THE  DAWN  OF  ART        283 

burrowing  worms,  for  long  sponge-spicules  radiate 
out  in  all  directions,  forming  an  effective  chevaux  de 
frise  either  at  the  mouth  of  the  shell  or  all  over  the 
body  of  the  builder. 

Another  extraordinary  instance  of  unconscious 
skill  is  to  be  found  in  the  shell  of  a  species  of  Psam- 
mosphsera  dredged  by  Mr.  Earland  on  the  Gold- 
seeker  in  the  North  Sea  in  happier  days  than  these 
(1915).  This  creature,  which  lives  on  very  muddy 
parts  of  the  sea-floor,  uses  long  sponge-spicules 
(2-3  mm.  in  length)  to  form  the  foundation-poles 
of  an  open  framework  or  chamber.  "  The  open 
spaces  in  the  wall  are  then  filled  in  with  fragments 
of  spicules  carefully  selected  for  length  so  as  exactly 
to  fill  the  spaces  that  are  to  form  the  walls  of  the 
test,  an  awkward  triangular  terminal  space  being 
frequently  filled  in  with  a  truncated  triaxial  spicule." 
The  creature  lives  in  its  roughly  spherical  house,  and 
the  projecting  ends  of  the  long  spicules  serve  as 
"catamaran  spars"  to  support  the  whole  on  the 
surface  layer  of  the  ooze.  And  the  wonder  of  adap- 
tation does  not  end  here,  for  we  read  that  a  second 
and  often  a  third  individual  will  in  the  building 
of  its  house  make  use  of  the  extreme  ends  of  long 
spicules  which  project  from  its  neighbor's  construc- 
tion. Two  or  three  individuals  united  in  this  way 
by  their  "  catamaran  spars  "  remain  entirely  distinct 
organisms,  "  their  only  connection  with  one  another 
being  a  purely  utilitarian  one,  the  association 
offering  greater  resistance  to  the  mud  than  a  single 
individual  can  attain."  It  is,  as  Mr.  Heron-Allen 


284  SECRETS  OF  ANIMAL  LIFE 

says,  like  the  beginning  of  a  "  social  instinct."  We 
make  no  apology  for  quoting  these  details,  for  the 
discoveries  are  of  high  importance,  increasing  our 
appreciation  of  the  subtlety  of  living  organisms 
even  in  their  relatively  simple  unicellular  expression. 
As  we  have  noted,  recourse  must  be  had  to  tough- 
minded  and  skeptical  experiment  (and  happily  it  is 
not  difficult  to  keep  Foraminifera  alive  in  artificial 
conditions),  but  it  seems  at  present  that  we  must 
attribute  to  creatures  at  the  level  of  the  Protozoa 
some  of  that  skil fulness  in  the  use  of  materials 
which  we  are  familiar  with  at  higher  reaches  of  the 
animal  kingdom — among  the  tube-building  worms, 
the  tailor-crabs,  the  hive-bees,  the  trap-door  and 
web-spinning  spiders,  and  so  on  up  to  the  nest- 
building  birds.  Just  as  we  have  rational  skill  and 
intelligent  skill  and  instinctive  skill,  so  perhaps  we 
have  in  these  Foraminifera  organic  skill,  when  the 
simple  individuality,  pulling  itself  together,  acts  as 
a  unity  and  then  perhaps  feels  itself  as  one.  For 
it  is  not  fantastic  to  suppose  that  in  such  critical 
moments  of  endeavor  and  adventure  consciousness 
first  found,  and  still  finds,  its  simplest  glimmering 
expression.  Perhaps  we  are  nearer  the  truth  in  sup- 
posing that  Technitella  says  to  itself  in  a  quiet 
way  of  its  own,  "  Anch'io  sono  pittore,"  than  in 
supposing  that  its  artifice  is  describable  in  terms  of 
surface-tension.  Those  interested  in  these  deep 
problems  will  watch  with  interest  the  progress  of 
Mr.  Heron-Allen's  and  Mr.  Earland's  investigations 
in  continuance  of  those  of  which  we  have  here 


BEFORE  THE  DAWN  OF  ART        285 

given  some  indication.  It  is  difficult  indeed  to 
break  off.  How  extraordinarily  quaint,  for  instance, 
it  is  to  read  of  the  probability  at  least  that  Saccam- 
mina  now  and  then  breaks  down  its  barns  to  build 
greater,  "  re-dissolving  the  cement  with  which  its 
house  is  built,  with  a  view  to  increasing  its  size 
by  the  interstitial  addition  from  within  of  stored 
material " !  How  we  are  made  to  think  by  the 
story  of  Marsipella  spiralis,  which  arranges  its 
borrowed  sponge-spicules  in  a  left-handed  spiral 
and  embeds  them  firmly  in  cement,  thus  improv- 
ing on  the  shell  of  its  neighbor-species  Marsipella 
cylindrica,  which  forms  a  long  and  exceedingly 
friable  tube !  "  It  would  appear  that  a  long  series 
of  generations  of  Marsipella  cylindrica  having 
suffered  from  this  extreme  friability,  it  was  left  for 
"Marsipella  spiralis  to  make  the  same  great  discovery 
as  did  the  prehistoric  genius  who  invented  string — 
it  has  clearly  realized  that  a  twisted  yarn  is  stronger  \ 
than  an  untwisted  wisp  of  fiber."  This  description 
is  indeed  rather  more  anthropomorphic  in  phrase- 
ology than  we  care  for,  but  we  venture  to  think  that 
it  errs  on  the  right  side.  Claparede  and  Lachmann, 
writing  in  1858  (when  the  Origin  of  Species  was 
published),  spoke  of  the  "absurdity"  of  supposing 
that  the  complicated  shell  of  a  Foraminifer  could  be 
secreted  by  "  an  amorphous  and  scarcely  organized 
mass  of  jelly."  '  The  animal  cannot  be  just  a  mass 
of  sarcode."  Something  is  now  known  in  regard  to 
the  intricacy  of  protoplasmic  organization,  but  we, 
speaking  for  ourselves,  would  still  say :  "  The 


286          SECRETS  OF,  ANIMAL  LIFE 

animal  cannot  be  just  a  mass  of  sarcode."  It  is 
that,  no  doubt,  but  there  is  another  side  to  the 
little  fraction  of  reality  which  we  call  Technitella. 
It  is  a  psycho-physical  individuality  whose  experi- 
ments in  self-expression  include  a  masterly  treat- 
ment of  sponge-spicules,  and  illustrate  that  organic 
skill  which  came  before  the  dawn  of  art. 


XXXVII 
MAN'S  ARBOREAL  APPRENTICESHIP 

MANY  distinguished  anatomists  have  referred 
to  man's  attainment  of  the  erect  position 
as  the  beginning  of  a  new  epoch,  and  have  shown 
how  walking  upright  upon  the  earth  would  affect 
not  only  hands  and  feet,  but  brain  and  vocal  organs. 
The  picture  usually  suggested  is  that  of  "  the 
turning  of  an  ordinary  quadruped  a  quarter  of  a 
circle  into  the  vertical  plane,"  and  we  are  asked 
to  think  of  the  "  slow  and  painful  acquisition  of  a 
radically  new  posture."  It  must  be  noticed  that 
bipedal  progression  has  originated  many  times  over 
1 — in  giant  reptiles  like  the  great  Iguanodons  (such  a 
striking  feature  of  the  Museum  of  Brussels),  in 
birds,  in  kangaroos  (if  they  are  not  tripods),  in  the 
jerboas  of  the  desert,  and  in  other  adventurous  types. 
Saville  Kent  has  given  a  lively  description  of  a  big- 
collared  Australian  lizard  (Chlamydosaurus)  which 
gets  up  on  its  hind  legs,  takes  a  little  tottering  run, 
and  collapses  like  a  baby  learning  to  walk.  Such 
cases  are  interesting,  for  they  warn  the  zoologist 
against  being  too  sure  about  what  a  living  creature 
cannot  do.  Bipedal  progression  has  been  tried 
over  and  over  again,  and  we  may  witness,  though 
with  anything  but  pleasure,  the  possibilities  of 

287 


288  SECRETS  OF  ANIMAL  LIFE 

it  in  performing  bipedal  dogs  and  bears.  But 
bipedal  progression  is  one  thing  and  the  upright 
position  is  something  more.  The  problem  is :  What 
induced  man  and  his  relatives  to  attempt  it  and 
persevere  in  it  successfully?  We  think  that  the 
answer  is  given  in  Professor  F.  Wood  Jones* 
recent  brilliant  study  of  "  Arboreal  Man,"  and  in  an 
earlier  not  less  brilliant  study  by  Dr.  R.  Anthony, 
a  French  zoologist. 

Professor  Wood  Jones  has  worked  out  very  con- 
vincingly the  thesis  that  Man  had  no  quadrupedal 
ancestry,  but  that  the  Primate  stock  to  which  he  be- 
longs was,  from  the  first,  bipedal  and  arboreal,  and 
that  the  leading  peculiarities  of  man  and  his  distant 
relatives  wrere  wrought  out  during  a  long  arboreal 
apprenticeship.  When  we  say  "  from  the  first "  we 
mean  from  the  time  when  the  Primate  race  diverged 
from  a  stock  of  generalized  placental  mammals,  or 
from  a  stock  of  bipedal  arboreal  reptiles,  represented 
perhaps  by  some  of  the  extinct  Therapsids.  It  is 
interesting  to  remember  the  view  of  some  experts 
that  birds  were  also  evolved  from  an  ancient  stock 
of  arboreal  reptiles.  All  these  pedigrees  are  hidden 
in  the  mist,  but  this  need  not  hinder  a  discussion 
of  the  organic  lessons  that  may  have  been  learned 
in  the  primeval  school  of  the  tree-tops.  The  first 
great  gain  of  arboreal  life  on  bipedal  erect  lines 
(and  not  in  the  fashion  of  sloths,  bats,  and  the  like) 
was  the  emancipation  of  the  hand.  The  typical 
quadruped  needs  its  fore  limb  as  a  stable  supporting 
pillar  and  organ  of  progression  upon  the  earth,  but 


MAN'S  ARBOREAL  APPRENTICESHIP     289 

what  a  door  was  opened  by  the  division  of  labor 
that  made  the  foot  the  supporting  and  branch- 
gripping  member,  and  set  the  hand  free  to  reach 
upward,  to  hang  on  by,  to  seize  the  fruit,  to  hug 
the  young  one  close  to  the  breast ! 

On  that  tack  of  evolution,  everything  we  value 
depended  on  setting  the  hand  free  from  the  sup- 
porting function  and  yet  keeping  it  generalized  and 
plastic.  For  the  human  hand,  so  often  misunder- 
stood, remains  a  generalized  structure,  able  for 
anything.  "  In  bones  and  in  muscles,"  Dr.  Wood 
Jones  says,  "  the  human  fore  limb  is  far  more  like 
that  of  a  tortoise  than  it  is  like  that  of  a  horse  or  a 
dog."  There  is  some  sense,  indeed,  in  the  adage : 
"  Good  for  everything  is  good  for  nothing,"  but  the 
other  side  of  it  is  seen  in  the  plasticity  of  the  un- 
specialized  human  hand.  The  opposite  extreme 
is  seen  in  the  bat's  hind  leg,  which  was  also  freed 
from  the  supporting  function,  but  became  specialized 
into  a  mere  hook  by  which  the  creature  hangs  itself 
up  to  sleep.  For  us  the  important  event  was  the 
emancipation  of  the  hand,  and  the  fact  that  the 
hand  thus  set  free  was  plastic  and  generalized — 
open  to  adventure. 

The  arboreal  life,  with  an  emancipated  hand,  led 
on  to  an  increased  freedom  of  movement  of  the  thigh 
on  the  hip  joint,  to  an  adjustment  of  the  backbone 
as  a  supple  yet  stable  pillar  with  a  characteristic 
curve  in  the  region  of  the  loins,  to  an  adaptation  of 
musculature  for  balancing  the  body  on  the  leg,  to 
a  well-developed  collar-bone,  to  a  specialization  of 


290  SECRETS  OF  ANIMAL  LIFE 

thumb  and  big  toe  for  branch-gripping  purposes. 
Dr.  Wood  Jones  sets  one  thinking  when  he  notes 
that  some  rodents  (e.g.  the  tree  mouse,  Mus 
ramgarettce,  discovered  by  Dr.  Charles  Hose  in 
Borneo)  have  developed  very  perfectly  opposable 
thumbs  and  big  toes  upon  lines  exactly  similar  to 
the  Primates.  For  this  phenomenon  of  "con- 
vergence " — the  attainment  of  closely  similar  adap- 
tations by  unrelated  types — is  of  surpassing  interest. 
We  have  dealt  with  it  in  a  previous  study,  and 
referred  to  the  discussion  of  the  problem  by  Profes- 
sor Arthur  Willey  in  his  Convergence  in  Evolution 
(1912),  and  also  by  Professor  Henri  Bergson  in  his 
Creative  Evolution  (1911),  but  the  whole  riddle 
has  not  yet  been  read. 

The  evolution  of  a  free  hand,  able  to  grasp  the 
food  and  lift  it  to  the  mouth,  made  it  possible  to 
dispense  with  protrusive  lips  and  gripping  teeth, 
and  thus  there  began  the  recession  of  the  snout 
region,  and  the  correlated  enlargement  of  the  brain 
box  and  the  bringing  of  the  eyes  to  the  front.  There 
is  often  a  tax  to  pay  for  great  improvements,  and 
"  the  process  of  shortening  of  the  snout,  outstrip- 
ping the  process  of  reduction  of  the  dental  series, 
gives  rise  to  one  of  the  great  problems  of  modern 
dentistry — the  proper  treatment  of  the  many  evils 
arising  from  overcrowded  jaws/'  Moreover,  with 
the  reduction  of  the  lower  jaw  modern  man  seems 
to  be  in  some  danger  of  losing  his  chin,  and  Profes- 
sor Wood  Jones  does  not  look  with  pleasure  at  the 
prospect  of  "  the  dawn  of  a  chinless  aristocracy." 


MAN'S  ARBOREAL  APPRENTICESHIP      291 

But  to  return  to  the  branches,  another  arboreal 
acquisition  was  a  greatly  increased  power  of  turning 
the  head  from  side  to  side.  All  ordinary  mammals 
can  say  "yes,"  raising  and  lowering  their  heads; 
but  the  ability  to  say  "  no "  with  emphasis  was 
gained  by  the  arboreal  Primates.  And  it  was  a 
great  advantage  to  be  able  to  move  the  head  so  as 
to  locate  sounds  and  supplement  the  mobility  of  the 
eyeballs.  To  arboreal  life  are  also  due,  according 
to  the  anatomist,  flat  chests  and  flat  backs;  and 
whereas  the  breathing  movements  of  the  ribs  count 
for  most  in  quadrupeds,  the  movements  of  the 
midriff  or  diaphragm  mean  most  to  tree-climbers 
and  modern  man. 

Except  in  special  cases,  such  as  marsupials  and 
nest-makers,  arboreal  mammals  tend  to  have  small 
families,  and  it  could  not  well  be  otherwise.  In 
the  great  majority  of  Primates  only  one  offspring 
is  born  at  a  time — a  reproductive  economy  which 
would  be  dangerous  were  there  not  a  correlated 
evolution  of  parental  carefulness.  All  mother- 
monkeys  carry  their  babies,  and  hold  them  in  their 
arms,  nursing  them  "  in  very  human  fashion,"  as 
Sir  Richard  Owen  said.  The  fathers,  too,  have 
repeatedly  been  seen  carrying  the  young  on  their 
arboreal  journeys.  Now,  the  fact  that  the  Simian 
parent  has  to  carry  the  very  immature  baby  about 
implies  an  intensification  of  the  family  relations;  it 
must  surely  have  favored  the  growth  of  gentleness. 

On  another  line  is  the  consideration  that  arboreal 
life  limits  the  usefulness  of  the  olfactory  organs, 


292  SECRETS  OF  ANIMAL  LIFE 

Touch  is  separated  off  from  the  nose  and  snout,  and 
is  specialized  in  the  hand.  "  It  is  the  freed  hand 
which  is  permitted  to  become  the  sensitive  hand, 
which  now,  so  to  speak,  goes  in  advance  of  the 
animal  and  feels  its  way  as  it  climbs  through  life." 
It  was  a  great  advance  when  the  hand  began  to 
be  habitually  used  to  corroborate  or  check  the 
impressions  gained  by  smell  and  by  sight. 

There  is  not  much  of  its  own  body  that  a  cat 
cannot  see  and  cannot  reach  with  its  tongue,  but 
this  is  far  from  being  usual  among  mammals,  and 
Professor  Wood  Jones  is  probably  right  in  attaching 
considerable  importance  to  the  way  in  which  the 
evolving  Primate  could  feel  with  its  hand  over  most 
of  its  body  and  could  also  picture  itself.  Theory 
apart,  it  is  certain  that  the  various  stages  of  brain- 
organization  seen  among  the  different  types  of 
monkeys,  show  a  decreasing  importance  of  the 
cerebral  area  for  receiving  olfactory  impressions  and 
a  predominance  of  the  neopallial  area  where  sensory 
impulses  from  hand  and  eye  and  ear  stream  in — 
an  area  towards  which,  moreover,  the  originative 
seats  of  the  outgoing  motor  impulses  tend  in  some 
mysterious  way  to  become  approximated.  It  is 
granted,  of  course,  that  cerebral  organization 
continued  to  make  progress  on  terra  firma  as  well  as 
among  the  branches,  but  the  point  is  that  arboreal 
life  was  peculiarly  favorable  to  the  evolution  of 
brains.  We  mean  that  the  arboreal  environment 
afforded  peculiarly  subtle  sieves  for  the  cerebral 
new  departures  which  were  always  cropping  up. 


MAN'S  ARBOREAL  APPRENTICESHIP     293 

It  may  be  objected  that  many  marsupials  are 
arboreal,  and  yet  they  do  not  seem  to  have  made 
much  of  their  educational  opportunities.  But  the 
answer  is  that  the  ground-plan  of  the  marsupial  , 
brain  is  different  from  that  of  placental  mammals 
and  precluded  great  advance.  As  to  the  problem 
whether  improvement  in  brains  brought  about  an 
increasing  manual  dexterity,  or  whether  bodily 
improvements  made  possible  a  cerebral  advance, 
Professor  Wood  Jones  gives  the  right  answer,  that 
the  two  sets  of  improvements  went  hand  in  hand. 
"  The  evolution  of  the  free  and  mobile  fore  limb 
in  arboreal  life  may  be  likened  to  the  production  of 
a  musical  instrument — an  instrument  upon  which  it 
is  impossible  for  the  animal  to  produce  a  full  range  , 
of  harmony,  or  to  appreciate  the  psychical  connota- 
tions of  this  harmony,  unless  adequate  cerebration 
is  developed  coincidently."  Perhaps  a  somewhat 
similar  answer  may  be  given  to  the  question  that 
confronts  us  at  every  turn:  How  all  these  adapta- 
tions to  arboreal  life  could  arise  if  functional  modi- 
fications acquired  by  individuals  are  not  entailed 
as  part  of  the  inheritance  of  the  race.  From  the 
fountain  of  change  hidden  in  the  dark  recesses  of 
the  germ-cells  there  is  a  welling  forth  of  tentatives 
and  initiatives,  but  it  rests  with  the  explicit  organism 
as  a  genuine  agent  to  put  these  variations  and 
mutations  to  the  test,  for  if  this  is  not  done  they  will 
profit  nothing,  and,  being  born  before  their  time, 
will  disappear  unappreciated. 


XXXVIII 
SEQUEL  TO  "  THE  JUKES  " 

THERE  was  recently  published  by  the 
Carnegie  Institution  of  Washington  one  of 
the  most  appalling  documents  in  Man's  strangely 
mixed  dossier — a  continuation  of  the  well-known 
"  study  in  crime,  pauperism,  disease,  and  heredity  " 
which  Mr.  R.  L.  Dugdale  completed  in  1877  anc^ 
entitled  "The  Jukes."  Mr.  Dugdale  was  a  quiet, 
reticent  Englishman,  resident  in  New  York,  who 
had  a  remarkable  faith  in  political  education,  and 
was  keenly  interested  in  social  problems.  On  an 
official  visit  to  county  jails  in  the  State  of  New 
York,  he  was  struck  by  finding  in  "  Z "  county 
six  prisoners,  under  four  family  names,  who  were 
blood  relations  in  some  degree.  He  interested 
himself  in  the  lineage  and  environment  of  these 
unfortunate  people,  and  was  able  to  study  709 
persons,  540  being  of  Juke  blood,  and  169  of  "  X  " 
blood  who  had  married  into  the  Juke  family.  He 
found  that  there  had  been  140  criminals  and  offen- 
ders, 60  habitual  thieves,  and  so  on,  the  degenerate 
lot  of  them  costing  the  State  in  seventy-five  years, 
beginning  with  1800,  far  over  a  million  dollars. 
What  his  work  showed  was  that,  given  a  bad  he- 
reditary "  nature  "  and  a  bad  environmental  "  nur- 


SEQUEL  TO  "  THE  JUKES  "          295 

ture,"  there  will  be  a  multiplication  of  criminality, 
harlotry,  and  pauperism.  It  should  be  noted,  if  it 
is  not  too  obvious,  that  the  name  Juke  was  fictitious, 
so  that  the  publication  of  "  The  Jukes  " — of  re- 
stricted circulation  in  any  case — did  not  induce  any 
Nemesis  analogous  to  what  follows  giving  a  dog  a 
bad  name.  But  the  chance  discovery  (in  1911)  of 
Mr.  Dugdale's  original  manuscript  has  made  it 
possible  to  recover  the  real  names,  and  with  these 
as  clues,  but  still  suppressed,  Dr.  Arthur  H.  Esta- 
brook  has  followed  up,  with  all  possible  carefulness, 
the  dismal  story  of  the  Jukes  down  to  1915.  The 
reason  for  referring  here  to  such  a  grim  subject 
was  expressed  long  ago  by  Huxley,  when  he  said: 
"  There  is  no  alleviation  for  the  sufferings  of  man- 
kind except  veracity  of  thought  and  of  action,  and 
the  resolute  facing  of  the  world  as  it  is." 

In  his  preface  to  the  sequel  to  "  The  Jukes," 
Dr.  C.  B.  Davenport,  the  indefatigable  director  of 
the  Laboratory  of  Experimental  Evolution  at  Cold 
Spring  Harbor,  gives  a  picture  of  the  headquarters 
of  the  Jukes  when  their  history  as  a  strain  began. 
"  Into  an  isolated  region,  now  within  two  hours' 
railroad  journey  of  the  nation's  metropolis,  there 
drifted  nearly  a  century  and  a  half  ago  a  number 
of  persons  whose  constitution  did  not  fit  them  for 
participation  in  a  highly-organized  society."  There 
were,  of  course,  various  degrees  of  inadequacy; 
and  the  retired,  well-wooded,  and  well-watered 
valley  (one  thinks  of  "  The  Country  of  the  Blind  ") 
doubtless  gave  many  of  the  immigrants  a  chance  to 


296  SECRETS  OF  ANIMAL  LIFE 

pull  themselves  together.  But  strains  with  damnosa 
hereditas  had  been  "  assisted  out "  from  Europe, 
and  from  such,  foreordained  to  perdition,  came 
"the  Jukes."  Here  are  some  of  them:  Max,  the 
hunter  and  fisher,  the  jolly,  alcoholic  ne'er-do-well; 
Lem,  the  stealer  of  sheep;  Lawrence,  the  licentious, 
free  with  his  "gun";  Margaret  and  Delia,  the  wan- 
tons; and  Bell,  who  had  three  children  by  various 
negroes.  Dr.  Davenport  continues :  "  Not  only  \vas 
much  of  the  original  stock  bad,  but  improvement 
which  might  otherwise  have  occurred  was  prevented 
by  constant  inbreeding.  The  nervous  weaknesses, 
the  mental  insufficiencies  were  thus  brought  together 
from  both  sides,  and  mentally  and  morally  defective 
offspring  wrere  rendered  more  certain.  Some  out- 
breeding  there  was,  and  where  it  was  with  better 
stock  the  progeny  had  better  intelligence  and 
emotional  control,  and  lines  were  founded  that 
were  able  to  hold  a  good  position  in  organized 
society." 

The  sequel  deals  with  the  now  widely-scattered1 
descendants  of  five  original  Juke  sisters,  a  total  of 
2094  people,  of  whom  1258  were  living  in  1915. 
The  most  general  fact  about  them  is  that  one-half 
were  and  are  feeble-minded  in  a  wide  sense,  "  men- 
tally incapable  of  responding  normally  to  the 
expectations  of  society,  brought  up  under  faulty 
environmental  conditions  which  they  consider 
normal,  satisfied  with  the  fulfilment  of  natural 
passions  and  desires,  and  with  no  ambitions  or 
ideals  in  life."  As  to  the  other  half  of  the  Jukes, 


SEQUEL  TO  "  THE  JUKES  "          297 

who  could  not  be  called  feeble-minded,  their  history 
seems  to  have  varied  mainly — as  does  that  of  most 
of  us — with  the  opportunities  of  social  "  nurture." 
But  all  this  is  too  vague :  let  us  take  more  precise 
acts.  In  1915  there  were  43  male  Jukes  between 
the  ages  of  15  and  18;  out  of  29,  whose  histories 
are  adequately  known,  "  18  are  anti-social,  doing 
poorly  in  the  world  at  large;  2  are  criminal,  while 
7  are  so  obviously  mentally  defective  as  to  be 
noticeable  to  the  general  community."  It  may  be 
noted  that  all  the  Juke  criminals  were  or  are  feeble- 
minded. Of  the  43  lads  referred  to  above,  19  are 
industrious.  The  number  of  males  over  19  and 
females  over  15  was  705  in  1915,  and  305  (or  43 
per  cent.)  of  these  are  "inimical  to  the  general 
welfare  of  the  community/'  41  are  criminal, 
103  mentally  deficient,  83  intemperate.  But  152 
are  industrious,  and  65  are  classed  as  "  good  citi- 
zens." Of  these  good  citizens,  we  are  told  that 
"  the  bad  traits  which  have  held  down  their 
brothers  and  sisters  have  become  lost,  and  they  are 
the  fountainheads  of  new  families  of  socially  good 
strain."  The  word  "  lost  "  is  arresting.  It  may  be 
that  some  of  the  bad  traits  illustrate  Mendelian  in- 
heritance, and  may,  in  the  case  of  marriage  into  good 
stock,  be  entirely  absent  in  a  certain  proportion  of 
the  grandchildren  and  subsequent  descendants. 

On  his  laborious  study  of  the  Jukes,  Dr.  Esta- 
brook  bases  some  general  conclusions :  cousin-mat- 
ings  in  radically-defective  stock  produce  defective 
offspring,  even  when  the  parents  make  a  passable 


298  SECRETS  OF  ANIMAL  LIFE 

appearance;  there  is  a  clear  hereditary  factor  in 
licentiousness;  pauperism  indicates  bodily  or 
mental  weakness,  and  the  latter  is  linked  with 
criminality;  penal  institutions  have  little  beneficial 
influence  upon  persons  of  defective  mentality; 
one  in  four  Jukes  is  improved  socially  by  Children's 
Institutions;  a  change  of  environment  gives  the 
individual  a  new  opportunity  and  a  chance  of 
mating  into  better  families.  In  many  cases,  how- 
ever, the  ne'er-do-well  in  new  surroundings  finds 
another  like  himself.  Improved  social  environment 
demonstrably  counts  for  much  in  the  individual's 
development,  but  this  depends  on  the  response 
that  he  is  able  and  willing  to  make,  and  the  power 
of  response  depends  on  the  hereditary  constitution. 
Yet  "  heredity,  whether  good  or  bad,  has  its  comple- 
mental  factor  in  environment." 

Mr.  Dugdale  laid  emphasis,  as  we  have  said,  on 
the  deteriorative  effect  of  continuous  bad  surround- 
ings; Dr.  Estabrook's  study,  carefully  documented 
with  genealogical  trees,  shows  that  the  hereditary 
factor  is  in  some  cases  equally  important,  e.g.,  as 
regards  weak-mindedness.  It  is  probably  unjust  to 
trace  all  the  innate  deficiencies  of  later  date  to  the 
original  Juke  strain,  since  evils  bred  in  the  bone 
would  be  sometimes  accentuated  by  mating  with 
similarly  disposed  members  of  other  stocks.  As  to 
weaknesses  that  can  be  classed  as  Mendelian  unit- 
characters — a  question  very  partially  answered, 
it  must  be  noted  that  outbreeding  with  normal 
members  of  the  community  would  affect  the  dis- 


SEQUEL  TO  "  THE  JUKES  "  299 

tribution  of  the  characters  in  the  progeny,  but  would 
not  effect  their  disappearance. 

The  story  began  with  five  sisters,  and  from  them 
has  spread  all  this  welter  of  weakness  and  misery, 
crime  and  sinfulness.  And  it  is  not  in  America 
only  that  Jukes  abound !  The  facts  make  us  feel  the 
need  for  a  fuller,  deeper,  and  wider  recognition  of 
what  Mr.  Benchara  Branford,  in  his  magnanimous 
Janus  and  Vesta  (1916),  calls  "  that  lofty  principle 
of  hereditary,  collective  and  vicarious  responsibility, 
punishment  and  suffering,  inherent  in  the  East, 
binding  with  indissoluble  and  adamantine  chain 
into  compassionate  social  solidarity  generation  to 
generation."  What  can  be  done  to  prevent  this 
proliferation  of  evil?  The  suggestions  before  the 
world  are  fourfold.  (i)  The  first  is  literally  or 
metaphorically  surgical — the  sterilization  of  those 
whose  constitutional  deterioration  is  radical  and  in- 
dubitable. From  this  proposal  social  sentiment 
shrinks,  partly  because  it  is  coercive  and  infringes 
"  the  liberty  of  the  subject  " — rather  a  mockery  for 
many  a  poor  Juke;  partly  because  of  the  terrible 
mistakes  that  might  be  made  in  our  ignorance — 
which,  however,  memoirs  like  Dr.  Estabrook's  are 
rapidly  reducing;  and  partly  from  the  dread 
that  always  attaches  to  proposals  which  interfere 
"artificially"  with  "natural"  consequences.  (2) 
Less  drastic,  in  a  way,  but  also  affecting  the  liberty 
of  the  individual,  is  the  proposal  to  secure  the 
permanent  custodial  care  of,  let  us  say,  the  feeble- 
minded, to  begin  with.  Dr.  Estabrook  writes: 


300          SECRETS  OF  ANIMAL  LIFE 

"  Out  of  approximately  600  living  feeble-minded 
and  epileptic  Jukes,  there  are  now  only  three  in 
custodial  care.  It  is  estimated  that  at  the  end  of 
fifty  years  the  defective  germ-plasm  would  be 
practically  eliminated  by  the  segregation  of  all  of  the 
600."  (3)  A  third  proposal,  to  be  considered  very 
critically,  is  to  improve  bad  stock  by  letting  it 
mingle  with  good.  If  we  were  able,  as  we  are  not, 
to  distinguish  beforehand  between  characters  that 
blend  and  characters  that  Mendelise,  it  might  be 
practicable  to  get  a  passable  average  man  from  a 
good  mother  and  a  bad  father,  but  in  reference  to 
well-defined  characters  the  trend  of  investigation 
is  strongly  against  any  such  experimenting.  It  is 
probable  that  the  very  worst  thing  a  man  can  do  is 
to  taint  good  stock  with  bad.  The  children  of  such 
unions  may  turn  out  not  badly,  if  they  are  brought 
up  in  conditions  of  wholesome  nurture,  and  the  taint 
(if  a  unit-character)  may  be  wholly  absent  in  some 
members  of  subsequent  generations,  but  without 
the  aid  of  persistent  selection  it  cannot  disappear 
from  the  lineage.  When  children  genetically  sound, 
but  by  individual  malnutrition  weakly,  are  trans- 
planted to  good  environment,  they  often  do  well; 
and  if  they  grow  up,  settle  down  and  marry,  no 
stock  is  harmed.  But  Dr.  Davenport  justly  doubts 
the  wisdom  of  sending  "  much  bad  germ-plasm  to 
good  farming  communities  throughout  our  Middle 
West."  Dr.  Davenport  has  done  valuable  service 
to  the  science  of  genetics,  but  we  wish  he  had  not 
written  a  sentence  like  this :  "  It  is  probable  that, 


SEQUEL  TO  "  THE  JUKES  "          301 

in  the  long  run,  the  cheapest  way  to  improve  a 
bad  germ-plasm  is  to  scatter  it."  For  this  sen- 
tence, which  seems  to  us  extremely  dangerous,  is 
almost  certain  to  be  quoted  apart  from  its  context: 
"  I  do  not,  however,  recommend  this  course  as 
superior  to  segregation;  but  only  as  a  cheap  and 
somewhat  hazardous  substitute.  In  the  case  of 
the  Jukes  there  are  so  many  dominant  traits  of 
feeble  inhibition  that  scattering  them  is  like  scatter- 
ing firebrands — each  tends  to  start  a  fire  in  a  new 
place."  The  last  sentence  hits  the  nail  on  the  head. 
(4)  What  other  suggestion  is  there  save  the  ancient 
one,  to  get  at  the  real  through  the  ideal,  to  work 
back  to  the  old-fashioned  pride  of  race  and  pride 
in  wholesome  children,  to  cultivate  a  sense  of  the 
social  or  racial  aspect  of  marriage,  to  foster  rational 
prejudices  against  mismating,  and  to  raise  our 
standard  of  health  for  mind  and  body  alike? 


XXXIX 
THE  OPTIMISM  OF  PATHOLOGY 

ONLY  the  foolish  or  the  ignorant  can  speak 
light-heartedly  of  disease  with  its  malignant 
subtlety  and  spreading  trail  of  misery.  How  often 
the  microbe  blots  out  the  sun;  how  often  we  are 
staggered  by  the  corruptio  optinii  pcssima  seen  in 
the  dissolution  of  a  structure  that  stood  for  a 
generation  like  a  tower  four-square  to  the  winds; 
how  often,  in  spite  of  the  triumphs  of  modern 
medicine,  the  hydra-headed  irrepressibility  of  disease 
grips  us  like  a  nightmare !  Health  is  a  magnificent 
quality,  but  it  is  ever  cheek  by  jowl  with  disease; 
and  thus  arises  the  sinister  view,  of  which  William 
James  spoke,  that  "  beauty  and  hideousness,  love 
and  cruelty,  life  and  death  keep  house  together 
in  indissoluble  partnership."  But  without  talking 
nonsense  about  the  whiteness  of  blackness,  or  the 
goodness  of  evil,  it  is  perhaps  possible  to  bring 
forward  some  useful  considerations  in  regard  to  the 
optimism  of  pathology.  In  the  first  place,  there 
is  the  important  fact  that  apart  from  senescence 
and  parasites  large  and  small,  there  is  almost  no 
disease  in  wild  Nature.  Should  a  pathological 
variation  arise,  it  is  eliminated  before  it  takes  grip. 
Constitutional  disease  is  the  occurrence  of  a  meta- 


THE  OPTIMISM  OF  PATHOLOGY     303 

holism  out  of  place,  out  of  time,  and  out  of  tune, 
and  Nature  makes  short  work  of  such  unhandy 
idiosyncrasies.  What  then  of  potato  disease  and 
salmon  disease,  of  fowl  cholera  and  swine  fever, 
and  big-bud  on  our  currant  bushes  and  bee-disease 
in  our  hives?  The  list  may  be  lengthened  out, 
but  the  answer  is  probably  the  same  in  all  cases, 
that  these  diseases  are  microbic  or  parasitic,  not 
constitutional,  and  that  they  occur  in  artificial, 
humanly-contrived  conditions,  not  in  the  economy 
of  wild  Nature.  There  are  very  few  examples  of 
microbic  diseases  in  natural  conditions,  one  of  the 
best  known  being  a  bacterial  disease  in  sandhoppers, 
and  this  may,  for  all  we  know,  have  something  to 
do  with  sewage  or  the  like.  It  is  not  denied  that 
wild  animals  are  sometimes  widely  infected  with 
microbes  so  that  an  epidemic  results.  We  know  of 
a  sort  of  diphtheria  among  ring-doves,  and  it  may 
be  that  some  disease  was  responsible  for  the  extra- 
ordinarily rapid  disappearance  of  the  Passenger 
Pigeon.  But  what  is  maintained  is  that  such 
occurrences  are  rare  and  evanescent,  and  that  they 
are  usually  traceable  to  rapid  human  interference 
— to  introducing  new  tenants  into  a  region,  to  killing 
off  the  natural  eliminators  of  the  sickly,  to  per- 
mitting overcrowding,  to  an  infection  of  the  soil 
and  water,  and  so  forth.  As  to  grouse,  it  seems 
that  there  is  no  specific  disease  in  this  well-nigh 
sacred  bird,  but  that  the  removal  of  natural  sifting 
agencies  allows  of  the  accumulation  of  weaklings 
and  weaknesses.  The  contingent  of  parasites  which 


304          SECRETS  OF  ANIMAL  LIFE 

seems  to  be  kept  within  bounds  in  the  vigorous 
bird  may  increase  sevenfold,  spreading,  for  instance, 
to  new  organs,  and  this  may  give  the  death-blow. 
We  submit,  however,  that  in  wild  Nature,  "  un- 
tainted by  man's  misery,"  as  Shelley  said,  health 
and  disease  do  not  "keep  house  together  in  indis- 
soluble partnership."  As  to  the  alleged  occurrence 
of  caries  in  Permian  fossil-fishes  and  osteomyelitis 
in  a  cave-bear,  perhaps  it  is  not  unjustifiable  to 
regard  such  cases  with  a  little  suspicion. 

In  the  second  place,  are  we  not  a  little  apt  to 
forget  what  has  been  recently  emphasized  in  Pro- 
fessor J.  G.  Adami's  interesting  and  courageous 
Medidal  Contributions  to  the  Study  of  Evolution 
( 1918) ,  that  certain  uncomfortable  bodily  processes, 
often  included  under  the  category  of  disease,  are 
the  organism's  efforts  to  adjust  itself  to  what  is  in 
man's  case  an  extraordinarily  subtle  and  changeful 
environment — in  great  part  very  artificial?  Thus 
against  the  old  view  of  inflammation  as  essentially 
an  injurious  process  leading  to  the  destruction  of 
tissue,  we  have  the  modern  view,  firmly  associated 
with  the  work  of  Metchnikoff,  that  inflammation 
is  a  response  or  reaction  to  an  intruding  irritant, 
and  tends  to  counteract  its  deleterious  effects. 
The  reaction  may  be  inadequate  or  excessive,  for 
the  organism  cannot  be  perfectly  adapted  to  every 
casualty.  But  inflammation  is  none  the  less  in  the 
direction  of  repair  and  self-preservation.  What  we 
should  marvel  at  is  not  human  disease,  but  the 
many-sidedness  of  our  power  of  counteracting  the 


THE  OPTIMISM  OF  PATHOLOGY     305 

assaults  of  microbes  and  poisons.  Professor  Adami 
writes:  "  As  shown  by  Sir  William  Leishman's 
simple  and  beautiful  experiment  (which  formed  the 
basis  of  Sir  Almroth  Wright's  opsonic  technique), 
there  is  not  one  pathogenic  microbe  which  cannot 
be  shown  to  be  taken  up  and  digested  sooner  or 
later  by  the  polymorpho-nuclear  leucocytes  of  the 
human  blood."  That  our  marvelously  well-equipped 
bodyguard  occasionally  fails  should  not  lead  us  to 
forget  its  normal  success  in  counteracting  assaults 
and  intrusions.  We  are  not  at  all  convinced  by 
Professor  Adami's  arguments  in  support  of  the 
thesis  that  inborn  capacities  for  resisting  disease 
are  the  hereditary  outcome  of  individual  bodily 
adjustments  in  the  same  direction;  or  that  evolu- 
tion, whether  progressive  or  retrogressive,  is  "  the 
outcome  of  an  active  process  of  continuous  adjust- 
ment between  organisms  and  their  environment," 
if  by  "  adjustment "  is  meant  a  direct  reaction  on 
the  part  of  the  living  matter  to  its  environment; 
but  we  think  that  he  has  done  good  service  in 
calling  attention  afresh  to  the  great  importance  of 
individual  bodily  modifications,  the  direct  results  of 
environmental  and  functional  peculiarities,  in  show- 
ing that  these  are  often  effectively  self -preservative, 
and  in  suggesting  what  still  remains  a  rather  vague 
hypothesis,  that  peculiarities  in  surrounding  influ- 
ences may  in  some  way  that  we  do  not  understand 
serve  as  the  stimuli  of  variations,  more  deeply  seated 
than  the  dents  and  imprints  which  are  technically 
called  modifications.  What  many  will  find  the 


306          SECRETS  OF  ANIMAL  LIFE 

most  interesting  contribution  of  the  book  is  the 
discussion  of  what  Professor  A'dami  calls  "  the  law 
of  habit."  Once  the  cells  of  the  body  of  a  rabbit 
have  got  accustomed  to  producing  a  counteractive 
or  anti-toxin  to  ricin  (from  the  castor-oil  plant), 
they  may  go  on  producing  anti-ricin  for  weeks  or 
months  after  the  original  stimulus.  In  the  horse 
a  single  toxin  unit  of  tetanus  can  lead  in  the  process 
of  immunization  to  the  production  of  1,000,000  anti- 
toxin units.  Ptyalism  may  persist  for  a  year  after 
a  dose  of  mercury.  A  cold  in  the  head  may  con- 
tinue for  weeks  after  the  causative  agent  has  dis- 
appeared and  thorough  sterilization  of  the  nose  has 
been  effected.  The  cells  form  a  habit,  it  may  be 
an  entirely  new  habit,  and  it  lasts,  "  an  acquired 
cell  variation  becoming,  if  I  may  so  express  it, 
converted  into  a  cell  heredity."  In  somewhat 
the  same  way  we  may  speak  of  microbes  acquiring 
new  habits,  for  the  indifferent  bacillus  may  become 
pathogenic,  and  the  virulent  may  be  tamed.  But 
tke  difficulty  is  to  pass  from  generations  of  cells 
and  of  unicellulars  to  the  very  different  case  of 
generations  of  multicellular  animals.  And  even  if 
we  suppose,  with  Professor  Adami  and  others,  that 
the  peculiarly  modified  body-cells  give  off  specific 
metabolites,  or  hormones,  or  messengers  of  some 
sort,  which  eventually  reach  their  goal  in  the  germ- 
cell  and  thus  specifically  affect  the  offspring — say 
in  the  direction  of  becoming  innately  immune  to 
some  poison — can  one  say  that  this  is  as  yet  more 
than  a  ballon  d'essai! 


THE  OPTIMISM  OF  PATHOLOGY     307 

In  the  third  place,  just  as  evil  is  a  tax  on  freedom, 
and  instability  the  penalty  of  genius,  so  it  seems 
legitimate  to  say  that  constitutional  disease  is  the 
seamy  side  of  variability.  Disease  is  often  just  a 
new  departure  that  has  gone  a  little  beyond  bounds. 
Sometimes  it  is  a  physiological  slipping  down  to  a 
lower  rung  of  the  evolution  ladder.  We  go  back 
to  our  definition  that  constitutional  disease  is  a 
type  of  metabolism  which  is  out  of  place,  out  of 
time,  and  out  of  tune.  It  is  interesting  to  notice 
that  what  would  be  pathological  in  one  animal  may 
have  become  normalized  in  another;  witness  the 
threads  from  the  male  stickleback's  kidney  with 
which  he  binds  the  water-weeds  into  a  nest,  or  the 
necrosis  at  the  base  of  the  stag's  antlers  which  leads 
to  their  being  shed.  And  the  supra-salivation 
producing  the  material  out  of  which  the  sea-swift 
Collocalia  makes  the  fragile  "  edible  bird's-nest,"  is 
it  not  nearly  akin  to  ptyalism?  Similarly,  what  is 
normal  at  one  period  of  life  may  be  pathological  at 
another,  as  we  see  in  the  de-differentiation  which 
occurs  at  certain  stages  in  the  change  of  a  tadpole 
into  a  frog,  or  of  a  caterpillar  into  a  butterfly. 
Looking  backwards,  we  see  that  just  as  pain  is  in 
part  interpretable  as  a  self -preservative  danger 
signal,  so  constitutional  disease,  practically  absent 
in  wild  Nature,  is  a  warning  to  man  of  the  dangers 
of  artificiality  and  foolhardy  defiance  of  the  funda- 
mental principles  of  physiology  ("  fools  afflicted 
because  of  their  transgression,"  as  the  Psalmist  put 
it).  We  see  also  that  many  processes  labeled  disease 


308  SECRETS  OF  ANIMAL  LIFE 

represent  the  organism's  best  efforts  to  counteract 
poison,  antagonize  assaults,  and  repair  injuries. 
We  see  also  that  constitutional  disease  is  after  all 
a  miss  out  of  many  hits,  a  failure  among  many 
successful  experiments,  a  tax  on  the  priceless  gift 
of  variability.  So  we  get  a  glimpse  of  the  optimism 
of  pathology. 


XL 
THE  CULT  OF  JOY 

IN  these  days  of  heavy  hear  13(1917)  the  publica- 
tion of  a  book  on  joy  does  not  seem  very  appro- 
priate, yet  what  Professor  Dearborn,  of  Cambridge, 
Mass.,  has  to  tell  us  makes  for  the  better  ordering 
of  life.  For  he  is  one  of  those  who  have  followed 
the  famous  physiologist  of  Petrograd,  Professor 
Ivan  Petrovich  Pavlov,  in  investigating  the  in- 
fluence of  the  emotions  on  the  health  of  the  body. 
That  a  good  circulation  is  associated  with  cheerful- 
ness is  a  familiar  fact — and  how  this  organic  jaunti- 
ness  sometimes  jars  on  the  tired  and  sorrowful! 
But  there  is  the  converse  proposition  that  cheer- 
fulness makes  for  health.  Organic  harmony  and 
vigor  are  correlated  with  gladness;  the  problem 
is  whether  the  joy  of  the  inner  life  has  any  real 
effect  on  the  organism's  working  power  and  staying 
power.  A  merry  heart  goes  all  the  day,  a  sad  one 
tires  in  a  mile;  but  was  not  the  merriness  the 
symptom  of  a  constitutional  indefatigability,  and 
the  sadness  a  sign  of  fatigue-toxins  already  elabor- 
ated? Dr.  Dearborn  seeks  to  prove  that  joy  is  a 
vera  causa,  and  it  is  interesting  to  inquire  how  he 
does  so.  Needless  to  say,  if  joy  be  regarded  as  a 
mere  luminescence  or  epiphenomenon  of  the  lively 

809 


310  SECRETS  OF  ANIMAL  LIFE 

particles  that  dance  unceasingly  in  the  mazes  of 
our  colloidal  substratum,  then  the  question  is  pre- 
judged. But  let  us  rid  ourselves  of  the  mechanistic 
superstition  and  give  Professor  Dearborn  fair  play. 
We  have  our  little  jokes  about  eupeptic  happiness, 
but  our  successors  will  smile  at  those  who  laughed 
at  one  of  our  author's  designations,  "  Psychologist 
and  Physiologist  to  the  Forsyth  Dental  Infirmary 
for  Children,  Boston." 

The  first  step  in  the  argument  is  that  when  our 
joyous  index  is  high  our  digestion  is  good.  As  Dr. 
Saleeby  has  put  it,  freedom  from  care  has  nutritive 
value.  As  was  said  of  old  time,  "  He  that  is  of  a 
merry  heart  hath  a  continual  feast,"  and  "  A  merry 
heart  is  the  life  of  the  flesh."  Now,  what  the 
researches  of  Pavlov,  Cannon,  Carlson,  Crile,  and 
others  have  done  is  to  demonstrate  experimentally 
that  pleasant  emotions  favor  the  secretion  of  the 
digestive  juices,  the  rhythmic  movements  of  the 
food-canal,  and  the  absorption  of  the  aliment. 
Contrariwise,  unpleasant  emotional  disturbance  and 
worry  of  all  sorts  can  be  proved  to  have  a  retarda- 
tive  influence  on  the  digestive  processes. 

When  the  hungry  man  sees  the  well-laid  table  his 
mouth  waters,  but  every  one  knows  that  a  memory 
or  an  anticipation  will  also  serve  to  move  at  least 
the  first  link  in  the  digestive  chain.  "  It  is  now 
well  known/'  says  Dearborn,  "that  no  sense- 
experience  is  too  remote  from  the  innervations 
of  digestion,  to  be  taken  into  its  associations,  and 
serve  as  a  stimulus  of  digestive  movements  and 


THE  CULT  OF  JOY  311 

secretions."  Emotion  may  influence  the  produc- 
tion of  adrenalin  by  the  core  of  the  adrenal  glands, 
and  a  slight  increase  in  this  powerful  substance 
constricts  the  smaller  blood-vessels,  raises  the  blood 
pressure,  excites  and  freshens  the  muscles,  increases 
the  sugar-content  of  the  blood,  and  so  on.  Good 
news,  psychical  if  anything  is,  may  set  in  motion 
a  series  of  physico-chemical  and  vital  processes, 
complex  beyond  the  ken  of  the  wisest.  And  the 
cheerful  man,  who  cultivates  the  habit  of  happiness, 
finding  reasons  for  rejoicing  in  the  sunshine  and  the 
stars,  in  flowers  and  birds,  in  works  of  art  and  the 
faces  of  his  friends,  will  have  his  "  joy-reward  "  or 
euphoria  added  unto  him  unless  he  is  fool  enough 
to  pursue  it. 

The  second  line  of  argument  refers  to  the  cir- 
culation. Wordsworth  was  a  better  physiologist 
than  he  knew  when  he  spoke  of  his  heart  leaping 
up  at  the  sight  of  the  rainbow,  or  filling  with 
pleasure  and  dancing  at  the  recollection  of  the 
daffodils.  He  may  not  have  kno\vn  much  about 
the  distribution  of  the  pneumogastric  nerve,  but 
he  knew  of  the  influence  of  joy  on  the  circulation. 
Experiments  have  been  made  by  prevaricating 
physiologists  who  take  the  pulses  of  whole  classes 
of  students,  give  them  milk-sugar  pills,  tell  them 
that  they  have  taken  heart  stimulants  or  heart 
depressants,  and  observe  after  a  time  the  change 
in  the  pulse  rates.  Many  of  the  hearts  beat  faster 
after  the  imaginary  stimulant,  and  slower  after 
the  imaginary  depressant,  but  what  is  more  inter- 


312          SECRETS  OF  ANIMAL  LIFE 

esting  is  that  the  changes  thus  induced  "by  idea- 
complexes,  formed  and  maintained  without  any 
emotion  "  are  small  compared  with  those  brought 
about  by  conditions  predominantly  emotional. 

Dr.  Dearborn  has  worked  at  the  factors  altering 
blood  pressure,  and  he  makes  the  notable  statement 
that  in  the  "  general  stimulation  of  the  essential 
circulation  in  all  constructive  parts  of  the  body, 
such  as  the  brain,  the  muscles,  and  the  digestive 
organs,  joy  exerts  one  of  its  most  conspicuous 
benefits,  and  one  that  no  one  can  doubt  or  ignore." 
It  is  interesting  to  ask,  though  we  may  never  be 
able  to  answer,  whether  the  apparent  joyousness 
of  many  birds,  expressed  especially  in  song,  but 
also  in  dance  and  exuberant  flight,  is  correlated 
with  their  singularly  perfect  digestive  capacity, 
their  fine  circulation  and  muscularity.  If  birds 
have  no  genuine  joie  de  vivre,  they  make  at  times 
an  extraordinarily  good  imitation  of  it,  and  we 
should  like  to  know  whether  they  are  eupeptic 
because  they  are  joyous,  or  joyous  because  they 
are  eupeptic.  For  sometimes  an  organism  is  a 
mind-body  and  at  other  times  a  body-mind. 

For  man,  however,  there  is  no  doubt  that  affective 
states  of  joy  and  grief  cause  rapid  changes  in  blood 
pressure.  "  In  one  case,"  Dearborn  tells  us,  "  an 
imaginary  kiss  caused  in  ninety  seconds  a  rise  of 
at  least  twenty  millimeters  of  mercurial  pressure; 
while  in  another  individual  a  suddenly  recalled 
grief  raised  it  in  less  time  thirty  per  cent,  more  than 
that."  A  large  variation  in  blood-pressure  in 


THE  CULT  OF  JOY  313 

persons  with  brittle  arteries,  as  they  so  often  are  in 
advanced  years,  might  lead  to  apoplexy,  and  the 
author  follows  Hack  Tuke  in  referring  to  the  alleged 
frequency  of  apoplexy  in  Philadelphia  in  the 
anxious  winter  of  1774-75,  and  in  Italy  in  1694-95, 
when,  as  the  chronicler  put  it,  "  all  commerce  was 
disturbed,  and  all  the  avenues  of  peace  blocked  up, 
so  that  the  strongest  heart  could  scarcely  bear  the 
thought  of  it."  As  the  siege  of  Paris  aged  many 
prematurely  or  otherwise  marked  them  for  the  rest 
of  their  days,  so  is  it  in  our  Great  War  tragedy. 
Therefore,  though  joy  be  far  from  us,  we  may  seek 
to  conserve  our  efficiency  by  calm  fortitude.  We 
cannot  go  to  the  "  Dr.  Merryman  "of  whom  Burton 
wrote  in  his  Anatomy  of  Melancholy,  but  we  may 
seek  out  another  whom  he  called  "  Dr.  Quiet." 

The  third  line  of  evidence  is  more  difficult  to 
follow*  than  the  two  others;  it  has  to  do  with  the 
influence  of  joy  on  the  nervous  system.  In  Sher- 
rington's  phrase,  the  supreme  function  of  the 
nervous  system  is  integrative — that  is  to  say,  it 
unifies  and  harmoniously  controls  the  activities 
of  thd  body  in  relation  to  one  another  and  to  the 
environment.  The  question  is,  Can  the  gladsome 
mind  increase  the  efficiency  of  this  integration? 
It  is  well  known  that  good  tidings  will  invigorate 
the  flagging  energies  of  a  band  of  explorers;  that 
an  unexpected  visit  will  change  the  wearied,  home- 
sick child,  as  if  by  magic,  into  a  dancing,  gladsome 
elf;  that  a  religious  joy  may  make  men  and  women 
transcend  the  ordinary  limits  of  our  frail  humanity. 


314          SECRETS  OF  ANIMAL  LIFE 

But  how  is  it  done?  How  does  the  oil  of  joy,  as 
the  Scriptures  call  it,  operate  in  making  the  limbs 
more  supple  and  the  face  to  shine? 

It  is  an  indubitable  fact  that  a  joy — say  of 
maternity,  or  discovery,  or  artistic  creation — may 
become  an  exhilaration  and  enthusiasm  of  thought 
and  will;  but  the  present  problem  is  rather  of  the 
bodily  welfare.  It  is  generally  believed  that  emo- 
tion has  its  physical  accompaniment  in  strains  and 
movements  throughout  the  body  and  in  changes 
in  the  secretion  of  glands;  and  it  is  certain  that 
this  reverberation  of  joy  is  for  good,  since  joy  is 
an  index  of  the  organism's  well-being.  It  is  also 
well-known  that  the  aesthetic  emotion — delight  in  the 
beautiful — is  very  markedly  a  body-and-mind 
reaction,  affecting  the  whole  creature  as  a  unity; 
but  the  problem  is  whether  joy  does  in  any  specific 
physiological  way  enhance  the  efficiency  of  the 
nervous  system.  Regarding  the  optic  thalamus 
of  the  brain  as  a  great  depot  of  sensory  influences 
and  as  a  center  of  emotional  reaction,  Dr.  Dear- 
born suggests  that  influences  from  this  region  may 
surge  up  into  the  cerebral  cortex,  the  seat  of  the 
higher  mental  processes,  where  joy  and  activity 
are  correlated.  He  speaks  tentatively  of  "a 
strong  afferent  or  ascending  flood  of  neural  influence 
through  the  optic  thalamus  (emotional  '  center') 
into  the  cortical  mid-layers";  but  whether  this 
means  much  or  little,  he  has  no  manner  of  doubt 
that  joy  has  a  direct  influence  on  the  integrative 
function  of  the  nervous  system, 


THE  CULT  OF  JOY  315 

Professor  Dearborn's  thesis  is  in  a  line  with 
many  other,  characteristically  American,  studies  in 
psychobiology,  which  aim  at  a  cultivation  of  the 
personality  on  what  one  may  call  direct  lines.  The 
danger  ahead  is  well  known,  that  just  as  the  direct 
pursuit  of  health  is  apt  to  engender  hypochondria 
and  valetudinarianism,  and  just  as  the  direct  pur- 
suit of  happiness  is  apt  to  defeat  its  own  end,  so 
the  direct  pursuit  of  joy  for  the  sake  of  the  "  joy- 
reward  "  may  prove  consummately  futile.  But  it  is 
possible  to  make  a  bogy  of  this  risk.  Forced  cheer- 
fulness is,  of  course,  a  horror,  but  "the  persistent 
will  to  be  glad,"  if  worthily  satisfied  with  some 
of  the  real  joys  of  life,  may  soon  become  a  habit 
which  requires  no  artificial  stimulation.  A  con- 
ventional approach  to  Nature  and  Art  is  often 
rewarded  much  beyond  its  deserts,  and  men  who 
began  with  taking  walks  for  duty's  sake  have  often 
become  genuine  enthusiasts  for  the  open  country. 
The  pursuit  of  joy  may  be  futile  and  the  faking  of 
it  an  abomination,  but  there  is  nothing  absurd,  for 
instance,  in  humbly  learning  to  know  the  endless 
things  of  beauty  which  are  joys  for  ever.  If  we 
make  sure  of  these,  the  euphoria  will  look  after 
itself. 


INDEX 


Acquired  characters,  question  as  to 

their  transmissibility,  221-223. 
Acquired     vigor,     does     it     count? 

263-269. 

Adami,  Professor  J.  G.,  his  studies 
on  disease  and  evolution,  304, 
305,  306. 

Agar,  Dr.,  his  experiments,  224. 
Algae,  Si,  82,  86. 

Allen,  Dr.  E.  J.,  his  demonstration 
of  the  correlaton  between  sun- 
shine records  and  the  quantity 
of  mackerel  at  Billingsgate,  80. 
Allen,    Glover    M.,    his    book    on 

Whalebone  Whales,  71. 
quoted,  76,  77. 

Amazon  ants,  raids  of  the,  17-23. 
"  Anguillulid  Nematodes,"  175. 
Anguillulid  worms,  179. 
Anguis  fragilis,   167. 
Anthony,  Dr.  R.,  French  zoologist, 

288. 

Ants,  Amazon,  raids  of  the,   17-23. 
Brown,   19,  20,  23. 
maternal  care  of  worker-,  272. 
Mediterranean,    186. 
white,  shedding  of  wings  of,  170. 
Ants   and   bees,   experimental   work 

with,   7. 

Aphaenogaster  barbarus,  186 
Apiary,    large,    pleasant    impression 

'of  sound  of,   1 06. 
Armadillo,  Hairy,  161. 
Hybrid,    162. 
Little,   159. 

Nine-banded,    158-159,    160,    161- 
162. 


Aromatic     compounds     in     various 

plants,  96-97. 

Art,  before  the  dawn  of,  278-286. 
Aspergillus  niger,  187. 
Autotomy,   168-173 
Autumn,     characteristic     sights     of, 

113-114. 

delight  and  quietness  of,   111-112. 
problems    of    the    natural    history 

of,    1 1 6. 

scientific  interest  of,    112-113. 
tactics  of,  1 1 6- 1 1 8. 
the    withering    and    fall    of    the 

leaves,   114-115. 

"  Auxetics  "      and      "  augmentors," 
132. 

Balaena  mysticetus,  78 

glacialis,   71. 
Bataillon's    method    of    fertilization 

of  frog's  eggs,   140. 
Bateson,  232,  240. 
"  Beagle,"    Voyage    of   the,    quoted, 

82,    93- 
Beavers,  271. 

Becquerel,     M.     Paul,     his     experi- 
ments on   seeds    177-182 
Beddard,     Dr.     F.     E.,     on    whales, 

78. 
Bees,   storing  instinct  in,    184,    185. 

worker,   maternal  care  of,   272. 
Beetles,  Burying,  limitation  of  their 

instinct,    209. 

Before  the  dawn  of  art,  278-286. 
Bergson,     Professor    Henri,    on    in- 
stinctive behavior,  210 
on   the  resemblance  between  the 


317 


318 


INDEX 


scallop's    and    the    vertebrate's 
eye,  257-258. 
quoted,  230,  290. 

Bernard,  Claude,  his  work  on  the 
phenomena  of  life,  178-179, 
1 80. 

Biology,   of  spring,    151. 
of  twins,   158-165. 

Bipedal  progression,  287-288. 

Blackburn,  Mrs.,  accuracy  of  her 
drawing  of  young  cuckoo  clear- 
ing nest  by  force,  46. 

Blegvad,  Dr.,  on  detritus-eating 
creatures,  86. 

Bonhote,  J.  Lewis,  his  breeding  ex- 
periments, 265-266. 
on   vigor  and   heredity,   264,   266- 
269. 

Boulenger,  Dr.,  quoted,  on  frogs, 
47- 

Brachet,  Professor,  his  lectures  on 
the  egg,  134,  136,  138. 

Brandt,  Professor,  on  Plankton  in 
polar  and  tropical  seas,  85-86. 

Branford,  Benchara,  quoted,  299. 

Brer  Rabbit's  policy,   128. 

Bullen,  G.  E.,  his  demonstration  as 
to  the  correspondence  between 
the  catches  of  mackerel  and  the 
amount  of  Copepod  plankton, 
80. 

Burroughs,  John,  quoted,  218-219, 
262. 

Burton,  Robert,  quoted,  313. 

Butler,   Samuel,  quoted,  25,  223. 

Csesar,  the  motive  of  his  expedition 
into  Britain,  67. 

Cairngorms,  their  slopes  in  winter, 
127,  129,  132. 

Caterpillars,  Procession,  their  in- 
stinct limited,  210. 

Cave  blindness,  the  problem  of, 
246-253. 

Cerambyx   beetle,   grub   of,   208-209. 

Chamberlin,    Professor,    on   the   ori- 


gin of  life  on  the  earth,   214, 
217,   218. 
Chambers,    Robert,   on   the   embryo, 

148. 

Change,  the  fountain  of,  238-245. 
the    problem    of    what    brings    it 

about,  238-239. 
Characteristic    sounds    of    particular 

places,    108-109. 
Cheerfulness.     See  Joy. 
Child,   Professor  W.   M.,   on   senes- 
cence  and  rejuvenescence,    151, 
IS3-I57- 

Chimpanzee,  restless  habits  of,   195. 
Chlamydosaurus,  287. 
Chromosomes,  number  of,   136,   137, 

138,  242-243,  244. 
Claparede,   285. 
Cod,  journeyings  of,    196. 
Convergence    in    evolution,    254-262. 
of   Australasian   animals,   256-257. 
three   suggestions  with   regard  to, 

259-261. 

Copepod  plankton,  80,  81,  84,  87. 
Correns,  232. 
Country  sounds,    104-110. 
Cowrie    shells    and    symbolism,    64, 

68-70. 

Crab,  common,  journeyings  of,   196. 
Crime.       See      Sequel      to      "  The 

Jukes." 

Crustaceans,    autotomy    in,    170-172. 
freshwater,      their      survival       of 

drought,    176. 
Cuckoo  puzzles,  39-46. 
Cuckoos,       resentful      attitude       of 
hedge-sparrow    and    little    birds 
to,    40-41. 
resemblance    of    eggs    to    selected 

foster-parent,    44. 
securing     success     for    their     off- 
spring,  272. 

smallness  of  their  eggs,  44. 
their   abundance  in   1916,   39. 
their   calls,    39-40. 
their   evasion   of   brooding,   41-43. 


INDEX 


319 


young  cuckoo's  behavior  in  nest, 

44-46. 

Cyon's  theory,  that  birds  nose  their 
way  home  through  the  air,  6. 

Dakin,  Dr.  W.  J.,  on  the  food  of 

the  Copepods,  81. 
Darwin,      Charles,      going     forward 

with,   225-228. 
on  brain  of  the  ant,   134. 
Darwin,     Charles,    on    earthworms, 

184, 

on  heredity,  229. 
on  kelp,  93. 

on  two  Roman  snails,  55. 
on    water    discolored    by    minute 

floating  Algae,   82. 
referred  to,  206. 
Darwinism,  no  recantation  of,  224- 

225. 
Davenport,    Dr.    C.    B.,    his    studies 

on  "  rovers,"    191-196. 
on    "  The    Jukes,"    295-296,    300- 

301. 
De   Vries,   a   rediscoverer   of   Men- 

delian  clue,  232. 
his  study  of  mutations  and  their 

behavior,  240-241. 
Dearborn,     Professor,     observations 

on  his  book  on  joy,  309-315. 
Delage,  Professor  Yves,  his  method 
of   subjecting   ova   to    chemical 
action,    140. 
Diatoms,  81,  82,  87. 
Differences  in  degeneration  of  eyes 

of  cave  animals,  247-248. 
Digger-wasps,   270,   271,   273. 
Dinnet,  the  moor  of,  in  spring,  150. 
Disease,      almost      none      in      wild 

Nature,  302. 
the    organism's    efforts    to    adjust 

itself  to  environment,  304. 
the  seamy  side  of  variability,  307. 
Doflein,  248. 

Ducbatel's    hypothesis    as    to    sensi- 
tiveness of  retina  of  bird,  5. 


Dugdale,    R.    L.,    his    studies    on 
"  The  Jukes,"   294-295. 

Earland,  Mr.,  his  investigations  on 

shells,    282,    283. 
Earth,     the,     "  preparations "     that 

make    it    fit    for    a    home    for 

living    creatures,    213-216,    217- 

220. 
Earthworms,     storing     instinct     in, 

184. 
Ebrard,      incident      of      the      ants' 

cocoons  reported  by,   20. 
Egg,    the    microcosm    of    the,    134- 

141. 
Eigenmann,  Professor,  his  study  of 

cave-fishes,    250,    252. 
Embryos,    dwarf   and    Siamese-twin, 

141. 

Emery,     Professor     Carlo,     his     in- 
vestigations   on    the    European 

Amazon  ant,   17-23. 
Estabrook,     Dr.      Arthur     H.,     his 

sequel    to    the    story    of    "  The 

Jukes,"  295,  297-300. 
Eumenes  amedei,  207,  208. 
Euphausia,   penguins'   food,    13. 
Evening     Primrose,     mutations     of, 

240,  241,   242. 

Evolution,   convergence  in,    254-262. 
Evolution    of    the    free    hand,    288- 

293- 

Experiments  on  egg-cells,  140-141. 
on  homing  of  sea-swallows,  1-8. 
with   ants   and   bees,    7. 
Ewart,   on  seeds,    179. 

Fabre,    the   late   M.    Henri,    his   ob- 
servations  on   beetles,    185. 
his    observations    on    wonders    of 
instinct,    206-210. 

Fall   of  the  year,    111-119. 

Fall  of  the  leaves,    114-115. 

Fish  embryos,  experiments  on,  250, 
251. 

"  Floating  meadows,"  81-82,  88. 


320 


INDEX 


"Fluctuations"  and  "mutations," 
238-240. 

Foraminifera  or  chalk-forming  ani- 
mals, 278-281,  284. 

Forel,  Auguste,  his  observations  on 
ants,  18,  20,  22. 

Formica    sanguinea,    blood-red    ant, 

Foster,  Sir  Michael,  quoted,  on  the 
living  body,  104. 

Frankincense  and  myrrh,  95-102. 

Fremiet,  M.  Faure,  on  the  egg, 
136. 

Frog,   life-cycle  of,  47-54. 

Frogs'  eggs,  artificial  partheno- 
genesis of,  140. 

Gadow,  Dr.,  quoted,  on  the  frog,  47. 
Gain,    Dr.    Louis,    on    penguins    re- 
turning   to    same    rookeries    to 
breed,   n. 

Galton,    Sir    Francis,    his   insistence 
on     the    reality     of    transilient 
variations,   240. 
his    investigations    on    biology    of 

twins,   162-164,   165. 
his    studies    of    inheritance,    230- 

231 

referred  to,  223. 

Gates,    Dr.    Ruggles,    his    investiga- 
tions on  mutation  of  CEnothera, 
242-245. 
Geddes,   Professor  Patrick,  his  idea 

as  to  life-curve,   143. 
Giard,  Professor,  176. 
Gladstone,    Hugh    S.,    his    observa- 
tions and  statistics  on  rooks,  38. 
Globerigina,   279. 

Goal,  the  unseen,  the  way  in  which 
animals    persistently    work    to- 
wards,  270-277. 
Goethe,    quoted,    276. 
Goldfishes,   experiments  on,  249. 
Gorilla,   restless  habits  of,    195. 
Graham,     Thomas,     on     "  energia," 
216. 


Groos,  Dr.,   149. 

Gudernatsch,     his     experiments    on 
tadpoles,   147. 

Hedge-sparrow    shadowing    and    at- 
tacking cuckoo,  40. 
Heine,  his  definition  of  silence,  106. 
Hempelmann,    Dr.,    quoted,    on    the 

frog,  54. 

Henderson,    Professor,    on   the    ori- 
gin of  life   on  the   earth,   214, 
215,  216,  218. 
Henri,    Mme.,    her    experiments    on 

the  bacillus  of  anthrax,  241. 
Herdman,     Professor,     quoted,     on 

Diatoms,  82,  87. 
Heredity.      See     Sequel     to     "The 

Jukes." 

Heron-Allen,    Edward,    his    observa- 
tions on   shells,   278-286. 
Herrick,   Professor  F.   H.,  his  sug- 
gestion  as  to  cuckoos'   loss  of 
nesting  instinct,  43. 
Hippocampus,  256. 
Holmes,       Professor,      quoted,      on 
evolution  of  the  voice  in  verte- 
brates, 49. 

Homing  of  birds,  problem  of,   j. 
Hookham,   George,  226,  259  note. 
Hose,  Dr.  Charles,  290. 
House-that-jack-built  nutritive  chain 

of   sequences,   87,   91-92. 
Huber,    Pierre,    Swiss   entomologist, 

1 8,   22. 
Huxley,      quoted>      on      organisms, 

103-104. 
on  oysters,  64. 
on   the  cycle  of  life,    142. 
on  the  sufferings  of  mankind,  295. 
Hyper-sensitiveness   to   sounds,    103, 
107. 

Inflammation,  304. 

Instinct,  different  from  intelligence, 

210-21 1. 


INDEX 


321 


its  limitation  in  insects,   209-210. 
wonders  of,  206-212. 
"  Intelligence  "   of   Foraminifera  in 
their  shell-formation,   278. 

Jackson,  Wilfrid,  his  work  on 
shells,  63,  66,  68 

James,   Professor  William,  his  two- 
fold     division       of      mankind, 
84-85. 
quoted,  302. 

Janet,  M.  Charles,  his  formicaria  of 
brown  ants,  19. 

Jenner,  his  observations  on  young 
cuckoo  in  nest,  44-45,  46. 

Jones,  Professor  F.  Wood,  ob- 
servations on  his  study  of 
"  Arboreal  Man,"  288-293. 

Joy,  its  influence  on  the  circula- 
tion, 311. 

its  influence  on  digestion,  310. 
its     influence     on     the     nervous 

system,  313. 
the  cult  of,  309-315. 

"  Jukes,"  the,  sequel  to,  294-301. 

Kammerer,  Dr.,  his  experiments 
on  salamanders,  224-225. 

Kelp,  93. 

Kidd,  Benjamin,  on  artificial  nur- 
ture, 164-165. 

Kirkman,  F.  B.,  his  notes  regarding 
male  birds  and  their  mates,  34, 
36- 

his  comparison  of  cuck>o's  notes, 
40. 

Lachmann,  285. 

Lamarck,  getting  back  to,  221,  223, 
224. 

Lankester,  Sir  Ray,  referred  to,  29, 
61,  206,  223,  255. 

Lashley,  Dr.  K.  S.,  his  experi- 
ments on  homing  of  sea- 
swallows,  1-8. 

Latter,  O.  H.,  quoted,  on  frogs,  47. 


Leishman,   Sir  William,   305. 
Levick,        Staff-Surgeon        Murray, 
R.   N.,   his  observations   on  the 
Adelie  penguins,   9-16. 
Liebig's   idea   of   the   circulation   of 

matter  illustrated,  81. 
Life,  a  limb  for  a,   166-174. 
embryonic  period  of,   145. 
larval  period  of,   142,   144. 
latent,    175-182. 
the  curve  of,   142-149. 
varying  types  of,   147-149. 
Limb  for  a  life,  a,   168-174. 
Loeb,     Professor    Jacques,    his    ex- 
periments   on    fishes,    250,    251- 
252. 
his   method   of   subjecting   ova  to 

chemical   action,    140. 
on  Plankton  organisms,  86. 

Mackerel,  80,  81,  88. 

Macquenne,    experiments    on   seeds, 

1 80. 

Macrocystis  pyrifera,  93. 
Making  a  home  for  life,  213-220. 
Man's  arboreal   apprenticeship,   287- 

293- 
Marsipella  cylindrica,  285. 

spiralis,  285. 
Maspero,    M.,    his    non-success    in 

germinating   wheat   grains   from 

tombs  of  the  Pharaohs,   179. 
Mayflower's  encounter  with   whales, 

story  of,   76. 
Mendel,   the   experimental   work   of, 

230,  232-237. 
Mendeleeff,  217. 
Mendelian  classification  of  all  new 

characters    into    dominants    and 

recessives,    243. 
Mendelian   clue,   the,    231-237. 

its  rediscovery,   232. 
Mendelian     conception     of     inherit- 
ance,    its     three     fundamental 

ideas,    232-235. 
Mendelian  doctrine,  244. 


322 


INDEX 


Meredith,   George,  quoted,   10,    no, 

203. 

"Metabolism,"  264-265,  268. 
Metchnikoff,    on    cause   of    growing 

old,  152. 

on  inflammation,  304. 
Microcosm  of  the  egg,  134-141. 
Midwinter,   127-133. 
Milton,  quoted,  76,  130. 
Mitchell,  Dr.  Chalmers,  149. 
Modifications,   305. 
Moore,      Professor     Benjamin,     on 

contents  of  sea-water,  83. 
Morgan,  T.  H.,  his  experiments  on 

the  fruit-fly,  236. 
Murray,    Sir    John,    quoted,    81-82, 

86. 
Mus  ramgarettae,  290. 

Nansen,  in  Far  North,  127. 

on  restless  men,    195. 
Natural    selection    of    variations    a 

i' era    causa    in    evolution,    225, 

227-228. 

Neger,  on  ants'  food,   187. 
Nematodes,  in  food-canal  of  grouse, 

201. 
Newman,      Horatio      Hackett,      on 

biology  of  twins,   158-162. 
Newton,  Professor  his  theory  as  to 

cuckoos'   egg*,  44,   45. 
Noddy    terns,    homing    experiments 

on,   1-6. 

Noisiest  thing  in  the  world,  103. 
Nomadism,  191-197. 

two  kinds  of,    195. 
Norman,  Canon,  on  shells,  282. 

Odoriferous  gland  in  shrews,  99. 
Odoriferous    substances,    in    butter- 
flies and  moths,  97. 
in  hound's  tongue  and  mice,  100- 

101. 

in  insects,  98,  99. 
in  plants,  95-97. 


Odors    of    mammals    and    reptiles, 

98. 
CEcotrophobiosis,  nutritive  exchange, 

29,  31. 
(Enothera     lamarckiana,     240,     241, 

243- 

Ogneff,    his    experiments    on    gold- 
fishes,  249. 

Onneas,    M.    Kammerlingh,    his    re- 
frigerating laboratory,   180. 
Onychophera,    145. 
Otter,  its  catholicity  of  appetite,  121. 
its  intensity  of  parental  care,  122. 
its  playfulness,    123. 
its  resourcefulness,  124. 
its  roving  spirit,  124. 
its  scent,  121. 
its     test-time     during     prolonged 

frost,  125. 

the  survival  of  the,   120-126. 
Owen,  Sir  Richard,  291. 

Parasites,  differences  of,   199-200. 
effects   on  hosts,   201. 

great   mortality   from,   202. 
repulsiveness   of,    202-203. 
"  wildness "   and  devilry  of,   204. 

Parasitism,  the  problem  of,  198-205. 

Parker,  Professor  G.  H.,  quoted,  on 
sense  organs,  100. 

Parthenogenesis,    artificial,     139-140. 

Pathology,    the    optimism     of,    302- 
308. 

Paul,     J.     Herbert,     his     work     on 
Crustaceans,    170,    172. 

Pavlov,    Professor    Ivan    Petrovich, 
his      experiment      on      mouth- 
watering of  dog,   56-57. 
his     investigations      on      emotions 
and  bodily  health,  309,  310. 

Pearls,  66-68. 

Pearson,   Professor  Karl,   his  study 
of  inheritance,  231. 

Penguins,    Adelie,    observations    oa 
the  habits  of,  9-16. 

Peridinians,  81,  87. 


INDEX 


328 


Petersen,  Professor  C.  G.  Job.,  on 
sea-bottom  meadows  of  Danish 
waters,  89-94. 

Petersen  and  Jensen,  Danish 
naturalists,  on  organic  matter 
of  sea-floor,  83. 

Phalangidae,  169-170. 

Physa  gyrina,  common  water- 
snail,  56. 

Phyto-plankton,   81,   82,  86. 

Planarian  worms,    153-1 54- 

Plankton  organisms,  83,  84,  86,  89, 
90. 

Polyergus  rufescens,  slave-owning 
ant,  18. 

Pond-life  in  winter  and  spring, 
132. 

Primates,  288,  290-292. 

Problem  of  cave  blindness,  the, 
246-253- 

Problem  of  the  origin  of  the  dis- 
tinctively new,  238. 

Progressiveness  of  evolution,  227. 

Proliferation  of  evil,  four  sugges- 
tions to  prevent  the,  299*301. 

Proteus,  247,  249,  274. 

Psammosphaera,  283. 

Ptyalism,  306,  307. 

Purple   dye    from    sea-snails,    65-66. 

Putter,  Professor,  his  heresy  as  to 
sea-water,  83. 

Rana  esculent  a,  48. 

temporaria,  47. 
Raspail,  on  young  cuckoo's  conduct 

in  nest,  45. 

Rejuvenescence,   150-157. 
Reophax,  281. 

Riddle,  Professor  Oscar,  138. 
Rignano,  editor  of  Scientia,  223. 
Robinson,    Phil,    his    observation    as 

to     parent     birds'     "  peptoniza- 

tion  "  of  food  for  young,  36. 
Rooks,  cawing  of,  32-38. 

their  courtship,  nesting,  eggs,  and 

habits,  34-38. 


Roubaud,  Dr.,  his  discoveries  as  to 
domestic  economy  of  African 
wasps,  26-31. 

Roving  impulse,  the,  191-197. 

Saleeby,   Dr.,  quoted,  310. 
Salmon,  in  autumn,  113-114. 
Sea,  internal  economy  of  the,  80-87. 
Sea-cucumbers,   1 69. 
Sea-grass,  89-94. 
Sea-meadows,  82,  88-94. 
Sea-swallows,   homing  of,    1-8. 
Seeds,  dried,   177. 

experiments   on,    177,    180-181. 

germinative  power  of,   179. 

their  capacity  for  lying  low,  181- 

182. 
Selous,   Edmond,  quoted,  on  rooks* 

cawing,   33. 

Senescence,  151-152,  154-157. 
Senility,  151-152. 

Sense  of  smell,  differentiated  from 
that  of  taste,  99. 

in  insects,  98. 

in  man,  95-102. 

in  the  dog,   99. 
Sense  of  taste,  99,  100. 
Sequel  to  "The  Jukes,"  294-301. 
Shakespeare,   quoted,   87,    197. 
Shelley,  quoted,  304. 
Shells,  the  appeal  of,  62. 

the  cult  of,  62-70. 

the  delight  in,  62. 

their  decorative  value,  64. 

their  interest  to   students   of  hu- 
man history,  63. 

their  practical  value  for  food,  64. 

their  psychological  value  as  sym- 
bols and  charms,  64,  66-70. 
Shell-trumpet,  64-65. 
Sherrington,   Professor,   quoted,   99. 

3i3- 

Shipley,   Dr.,   198. 
Siamese  twins,   141,   159,   160. 
Smith,  Professor  Elliot,  on  the  cult 
of  shells,  63,  68,   69. 


324. 


INDEX 


Snail,  experiments  and  investiga- 
tions on  educability  of,  55- 
61. 

Sooty  terns,  homing  experiments 
on,  1-6. 

Sounds,  country,  generally  restful 
and  subdued,  103,  105. 

Spencer,   Herbert,   runs  away  from 

home  at  thirteen,   192. 
his  conviction  that  a  right  answer 
must  be  given  to  the  question 
whether  acquired  characters  are 
or  are  not  inherited,  221. 

Spring,  biology  of,  151. 
its     coming,     on     the    moor     of 
Dinnet,  150. 

Squirrels,  their  storing  instincts, 
1 88. 

Starfishes,    shedding    a    limb,    266, 

167,  169. 

Stevenson,  R.  L.,  quoted,  113. 
Storing  instinct,   183-190. 

among  birds,  187. 

among  insects,   184-187. 

among  mammals,  188-189. 

in  man,  189-190. 
Story   as   to   "  young  seals "   being 

"  so  like  birds,"   9. 
Stout,  Professor,  quoted,  on  smell, 

101. 
Sweet  Vernal  grass,  95. 

Tadpoles,       Gudernatsch's      experi- 
ments on,   147. 
their   power    of    regrowing   parts, 

1 68. 

See  also  Frog. 

Tapeworms,  198,  200. 

Technique  of  the  experiments  on 
homing  of  sea-swallows,  2. 

Technitella,  280,  282,  284,  286. 

Thompson,  Miss  Elizabeth  Lock- 
wood,  her  experiments  on 
snails,  56-61. 

Tower,  Professor,  his  experiments 
on  potato-beetles,  241. 


Tregarthen,  J.   C.,  his  observations 

on   the   otter,    120-126. 
Troglodytes,  246-247. 
Trypanosomes,   198,  202. 
Tschermak,   232. 
Twins,  biology  of,   158-165. 

Galton's    investigations    on,     162- 
164. 

Siamese,  159. 

similarity  between,  162-164. 

Van  Hoff's  law  of  the  effect  of 
temperature  on  chemical  re- 
actions, 129. 

Verhoeff,  on  wasp-community,  30. 

Vigor,  acquired,  does  it  count? 
263-269. 

Vigor  and  Heredity,  Mr.  J.  Lewis 
Bonhote's  book,  264-265. 

Wasp,     solitary,    its    perfection    of 

nest,  207-208. 

Wasps,  African,  26,  28-31. 
social  life  of,  24-31. 
their    family    coherence,    strength, 

and  ingenuity,  25-26 
their     instinctive     behavior,     270, 

271. 
their    wonderful    workmanship    Of 

their  nest,   24-25,   115. 
Watson,  Professor  J.  B.,  his  experi- 
ments    on      homing      of     sea- 
swallows,   1-8. 
his   observations  on  the   duration 

of  the  nesting  impulse,  7. 
Weismann,     Professor,     155,     223, 

229,  230,  255. 

Werber,  his  physiological  theory,  161. 
Whales,  Baleen,  72,  73. 

Black   North   Atlantic   or   Biscay, 

7i,   75- 

Black  Right,  78. 
Finback,  71. 

Greenland,  or  Bowhead,  78. 
Humpback,  71. 
Right,  the  fitness  of,  71-79. 
Whales,   Sperm,  71. 


INDEX 


325 


story    of    Mayflower's    encounter 

with,   76. 
their     extraordinary     adaptations, 

71-73. 
Toothed,  71. 

Wheeler.  Professor  W.  M.,  his 
studies  of  American  Amazon 
ants,  1 8,  277. 

White,  Gilbert,  quoted,  34,  184. 

Whitman,  Walt,  his  "World  below 

the  Brine,"  quoted,  94. 
quoted,  on  the  bustle  of  growing 
wheat,    104. 

Willey,  Professor  Arthur,  on  con- 
vergence in  evolution,  256, 
260-261,  290. 

Wilson,  Professor  E.  B.,  on 
Siamese-twin  embryos,  160. 

Wilson,  Professor  James,  on 
Mendelism,  235-237. 

Wilson,  the  late  Dr.  Edward  A., 
his  work,  10. 

"  Wireless "  messages  of  imagina- 
tion, 109. 


Winter,  birch  trees  in,   129. 

on  the  slopes  of  the  Cairngorms, 

127,  129,  132. 
pond-life  in,  132. 
silence  of,   127. 
stores  to  tide  over,  131. 
time  of  rejuvenescence,   128. 
vital    activity    and    its    breaking- 
point  in,  130. 
ways    in    which    living    creatures 

meet  stress  of,  130-131 
Wonders  of  instinct,  206-212. 
Wordsworth,  41,  311. 
Worms,  Anguillulid,  179. 

self -mutilation  of,  when  captured, 

168-169. 
Wright,  Sir  Almroth,  305. 

Zoo,  story  of  lady  and  the  penguins 

at,   9. 
story  of   Yankee  visitor  at,  with 

regard  to  the  giraffe,  73. 
Zostera,  sea-grass,  89,  90,  91. 


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